Fix frame synchronization with scroll bar movement

* src/xfns.c (x_set_inhibit_double_buffering): Stop condeming
scroll bars.

* src/xterm.c (x_scroll_bar_create): Create an InputOnly window.
Update event masks accordingly and stop allocating back buffer.
(x_scroll_bar_remove): Stop deallocating back buffer.
(XTset_vertical_scroll_bar, x_scroll_bar_set_handle): Draw onto
the edit window so they can be synchronized with buffer flips.
(x_scroll_bar_clear): Redraw scroll bars instead of just
clearing them.
(x_scroll_bar_handle_expose, x_scroll_bar_redraw): New
functions.
(x_scroll_bar_expose, x_scroll_bar_end_update): Delete
functions.
(handle_one_xevent): Update exposure logic accordingly.

* src/xterm.h (struct scroll_bar): Remove `x_drawable' field.

3 files changed, 195 insertions, 269 deletions

diff --git a/src/xfns.c b/src/xfns.c
index 579237068a2..1ae615fad44 100644
--- a/src/xfns.c
+++ b/src/xfns.c
@@ -838,21 +838,9 @@ x_set_inhibit_double_buffering (struct frame *f,
 
       block_input ();
       if (want_double_buffering != was_double_buffered)
-        {
-          /* Force XftDraw etc to be recreated with the new double
-             buffered drawable.  */
-          font_drop_xrender_surfaces (f);
-
-          /* Scroll bars decide whether or not to use a back buffer
-             based on the value of this frame parameter, so destroy
-             all scroll bars.  */
-#ifndef USE_TOOLKIT_SCROLL_BARS
-          if (FRAME_TERMINAL (f)->condemn_scroll_bars_hook)
-            FRAME_TERMINAL (f)->condemn_scroll_bars_hook (f);
-          if (FRAME_TERMINAL (f)->judge_scroll_bars_hook)
-            FRAME_TERMINAL (f)->judge_scroll_bars_hook (f);
-#endif
-        }
+        /* Force XftDraw etc to be recreated with the new double
+           buffered drawable.  */
+        font_drop_xrender_surfaces (f);
       if (FRAME_X_DOUBLE_BUFFERED_P (f) && !want_double_buffering)
         tear_down_x_back_buffer (f);
       else if (!FRAME_X_DOUBLE_BUFFERED_P (f) && want_double_buffering)
diff --git a/src/xterm.c b/src/xterm.c
index dc9637d35c7..6dd3aad0e01 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -1129,10 +1129,6 @@ static void x_initialize (void);
 static bool x_get_current_wm_state (struct frame *, Window, int *, bool *, bool *);
 static void x_update_opaque_region (struct frame *, XEvent *);
 
-#if !defined USE_TOOLKIT_SCROLL_BARS && defined HAVE_XDBE
-static void x_scroll_bar_end_update (struct x_display_info *, struct scroll_bar *);
-#endif
-
 #ifdef HAVE_X_I18N
 static int x_filter_event (struct x_display_info *, XEvent *);
 #endif
@@ -1142,6 +1138,10 @@ static struct frame *x_tooltip_window_to_frame (struct x_display_info *,
                                                 Window, bool *);
 static Window x_get_window_below (Display *, Window, int, int, int *, int *);
 
+#ifndef USE_TOOLKIT_SCROLL_BARS
+static void x_scroll_bar_redraw (struct scroll_bar *);
+#endif
+
 /* Global state maintained during a drag-and-drop operation.  */
 
 /* Flag that indicates if a drag-and-drop operation is in progress.  */
@@ -14627,20 +14627,12 @@ x_scroll_bar_create (struct window *w, int top, int left,
     XSetWindowAttributes a;
     unsigned long mask;
     Window window;
-#ifdef HAVE_XDBE
-    Drawable drawable;
-#endif
-
-    a.background_pixel = f->output_data.x->scroll_bar_background_pixel;
-    if (a.background_pixel == -1)
-      a.background_pixel = FRAME_BACKGROUND_PIXEL (f);
 
     a.event_mask = (ButtonPressMask | ButtonReleaseMask
-                    | ButtonMotionMask | PointerMotionHintMask
-                    | ExposureMask);
+                    | ButtonMotionMask | PointerMotionHintMask);
     a.cursor = FRAME_DISPLAY_INFO (f)->vertical_scroll_bar_cursor;
 
-    mask = (CWBackPixel | CWEventMask | CWCursor);
+    mask = (CWEventMask | CWCursor);
 
     /* Clear the area of W that will serve as a scroll bar.  This is
        for the case that a window has been split horizontally.  In
@@ -14648,32 +14640,22 @@ x_scroll_bar_create (struct window *w, int top, int left,
     if (width > 0 && window_box_height (w) > 0)
       x_clear_area (f, left, top, width, window_box_height (w));
 
+    /* Create an input only window.  Scroll bar contents are drawn to
+       the frame window itself, so they can be double buffered and
+       synchronized using the same mechanism as the frame.  */
     window = XCreateWindow (FRAME_X_DISPLAY (f), FRAME_X_WINDOW (f),
                             /* Position and size of scroll bar.  */
                             left, top, width, height,
-                            /* Border width, depth, class, and visual.  */
+                            /* Border width.  */
                             0,
+                            /* Depth.  */
                             CopyFromParent,
-                            CopyFromParent,
+                            /* Class.  */
+                            InputOnly,
+                            /* Visual class.  */
                             CopyFromParent,
                              /* Attributes.  */
                             mask, &a);
-#ifdef HAVE_XDBE
-    if (FRAME_DISPLAY_INFO (f)->supports_xdbe
-        && FRAME_X_DOUBLE_BUFFERED_P (f))
-      {
-        x_catch_errors (FRAME_X_DISPLAY (f));
-        drawable = XdbeAllocateBackBufferName (FRAME_X_DISPLAY (f),
-                                               window, XdbeCopied);
-        if (x_had_errors_p (FRAME_X_DISPLAY (f)))
-          drawable = window;
-        else
-          XSetWindowBackgroundPixmap (FRAME_X_DISPLAY (f), window, None);
-        x_uncatch_errors_after_check ();
-      }
-    else
-      drawable = window;
-#endif
 
 #ifdef HAVE_XINPUT2
   /* Ask for input extension button and motion events.  This lets us
@@ -14700,9 +14682,6 @@ x_scroll_bar_create (struct window *w, int top, int left,
 #endif
 
     bar->x_window = window;
-#ifdef HAVE_XDBE
-    bar->x_drawable = drawable;
-#endif
   }
 #endif /* not USE_TOOLKIT_SCROLL_BARS */
 
@@ -14775,14 +14754,11 @@ static void
 x_scroll_bar_set_handle (struct scroll_bar *bar, int start, int end,
                          bool rebuild)
 {
-  bool dragging = bar->dragging != -1;
-#ifndef HAVE_XDBE
-  Window w = bar->x_window;
-#else
-  Drawable w = bar->x_drawable;
-#endif
-  struct frame *f = XFRAME (WINDOW_FRAME (XWINDOW (bar->window)));
-  GC gc = f->output_data.x->normal_gc;
+  bool dragging;
+  struct frame *f;
+  Drawable w;
+  GC gc;
+  int inside_width, inside_height, top_range, length;
 
   /* If the display is already accurate, do nothing.  */
   if (! rebuild
@@ -14790,106 +14766,102 @@ x_scroll_bar_set_handle (struct scroll_bar *bar, int start, int end,
       && end == bar->end)
     return;
 
-  block_input ();
-
-  {
-    int inside_width = VERTICAL_SCROLL_BAR_INSIDE_WIDTH (f, bar->width);
-    int inside_height = VERTICAL_SCROLL_BAR_INSIDE_HEIGHT (f, bar->height);
-    int top_range = VERTICAL_SCROLL_BAR_TOP_RANGE (f, bar->height);
+  f = XFRAME (WINDOW_FRAME (XWINDOW (bar->window)));
+  dragging = bar->dragging != -1;
+  gc = f->output_data.x->normal_gc;
+  w = FRAME_X_DRAWABLE (f);
 
-    /* Make sure the values are reasonable, and try to preserve
-       the distance between start and end.  */
-    {
-      int length = end - start;
+  block_input ();
 
-      if (start < 0)
-        start = 0;
-      else if (start > top_range)
-        start = top_range;
-      end = start + length;
+  inside_width = VERTICAL_SCROLL_BAR_INSIDE_WIDTH (f, bar->width);
+  inside_height = VERTICAL_SCROLL_BAR_INSIDE_HEIGHT (f, bar->height);
+  top_range = VERTICAL_SCROLL_BAR_TOP_RANGE (f, bar->height);
 
-      if (end < start)
-        end = start;
-      else if (end > top_range && ! dragging)
-        end = top_range;
-    }
+  /* Make sure the values are reasonable, and try to preserve
+     the distance between start and end.  */
+  length = end - start;
 
-    /* Store the adjusted setting in the scroll bar.  */
-    bar->start = start;
-    bar->end = end;
+  if (start < 0)
+    start = 0;
+  else if (start > top_range)
+    start = top_range;
+  end = start + length;
 
-    /* Clip the end position, just for display.  */
-    if (end > top_range)
-      end = top_range;
+  if (end < start)
+    end = start;
+  else if (end > top_range && ! dragging)
+    end = top_range;
 
-    /* Draw bottom positions VERTICAL_SCROLL_BAR_MIN_HANDLE pixels
-       below top positions, to make sure the handle is always at least
-       that many pixels tall.  */
-    end += VERTICAL_SCROLL_BAR_MIN_HANDLE;
+  /* Store the adjusted setting in the scroll bar.  */
+  bar->start = start;
+  bar->end = end;
 
-    /* Draw the empty space above the handle.  Note that we can't clear
-       zero-height areas; that means "clear to end of window."  */
-    if ((inside_width > 0) && (start > 0))
-      {
-        if (f->output_data.x->scroll_bar_background_pixel != -1)
-          XSetForeground (FRAME_X_DISPLAY (f), gc,
-                          f->output_data.x->scroll_bar_background_pixel);
-        else
-          XSetForeground (FRAME_X_DISPLAY (f), gc,
-                          FRAME_BACKGROUND_PIXEL (f));
+  /* Clip the end position, just for display.  */
+  if (end > top_range)
+    end = top_range;
 
-        XFillRectangle (FRAME_X_DISPLAY (f), w, gc,
-                        VERTICAL_SCROLL_BAR_LEFT_BORDER,
-                        VERTICAL_SCROLL_BAR_TOP_BORDER,
-                        inside_width, start);
+  /* Draw bottom positions VERTICAL_SCROLL_BAR_MIN_HANDLE pixels
+     below top positions, to make sure the handle is always at least
+     that many pixels tall.  */
+  end += VERTICAL_SCROLL_BAR_MIN_HANDLE;
 
+  /* Draw the empty space above the handle.  Note that we can't clear
+     zero-height areas; that means "clear to end of window."  */
+  if ((inside_width > 0) && (start > 0))
+    {
+      if (f->output_data.x->scroll_bar_background_pixel != -1)
         XSetForeground (FRAME_X_DISPLAY (f), gc,
-                        FRAME_FOREGROUND_PIXEL (f));
-      }
+                        f->output_data.x->scroll_bar_background_pixel);
+      else
+        XSetForeground (FRAME_X_DISPLAY (f), gc,
+                        FRAME_BACKGROUND_PIXEL (f));
 
-    /* Change to proper foreground color if one is specified.  */
-    if (f->output_data.x->scroll_bar_foreground_pixel != -1)
-      XSetForeground (FRAME_X_DISPLAY (f), gc,
-                      f->output_data.x->scroll_bar_foreground_pixel);
+      XFillRectangle (FRAME_X_DISPLAY (f), w, gc,
+                      bar->left + VERTICAL_SCROLL_BAR_LEFT_BORDER,
+                      bar->top + VERTICAL_SCROLL_BAR_TOP_BORDER,
+                      inside_width, start);
 
-    /* Draw the handle itself.  */
-    XFillRectangle (FRAME_X_DISPLAY (f), w, gc,
-                    /* x, y, width, height */
-                    VERTICAL_SCROLL_BAR_LEFT_BORDER,
-                    VERTICAL_SCROLL_BAR_TOP_BORDER + start,
-                    inside_width, end - start);
+      XSetForeground (FRAME_X_DISPLAY (f), gc,
+                      FRAME_FOREGROUND_PIXEL (f));
+    }
 
+  /* Change to proper foreground color if one is specified.  */
+  if (f->output_data.x->scroll_bar_foreground_pixel != -1)
+    XSetForeground (FRAME_X_DISPLAY (f), gc,
+                    f->output_data.x->scroll_bar_foreground_pixel);
 
-    /* Draw the empty space below the handle.  Note that we can't
-       clear zero-height areas; that means "clear to end of window." */
-    if ((inside_width > 0) && (end < inside_height))
-      {
-        if (f->output_data.x->scroll_bar_background_pixel != -1)
-          XSetForeground (FRAME_X_DISPLAY (f), gc,
-                          f->output_data.x->scroll_bar_background_pixel);
-        else
-          XSetForeground (FRAME_X_DISPLAY (f), gc,
-                          FRAME_BACKGROUND_PIXEL (f));
+  /* Draw the handle itself.  */
+  XFillRectangle (FRAME_X_DISPLAY (f), w, gc,
+                  /* x, y, width, height */
+                  bar->left + VERTICAL_SCROLL_BAR_LEFT_BORDER,
+                  bar->top + VERTICAL_SCROLL_BAR_TOP_BORDER + start,
+                  inside_width, end - start);
 
-        XFillRectangle (FRAME_X_DISPLAY (f), w, gc,
-                        VERTICAL_SCROLL_BAR_LEFT_BORDER,
-                        VERTICAL_SCROLL_BAR_TOP_BORDER + end,
-                        inside_width, inside_height - end);
 
+  /* Draw the empty space below the handle.  Note that we can't
+     clear zero-height areas; that means "clear to end of window." */
+  if ((inside_width > 0) && (end < inside_height))
+    {
+      if (f->output_data.x->scroll_bar_background_pixel != -1)
         XSetForeground (FRAME_X_DISPLAY (f), gc,
-                        FRAME_FOREGROUND_PIXEL (f));
-      }
+                        f->output_data.x->scroll_bar_background_pixel);
+      else
+        XSetForeground (FRAME_X_DISPLAY (f), gc,
+                        FRAME_BACKGROUND_PIXEL (f));
+
+      XFillRectangle (FRAME_X_DISPLAY (f), w, gc,
+                      bar->left + VERTICAL_SCROLL_BAR_LEFT_BORDER,
+                      bar->top + VERTICAL_SCROLL_BAR_TOP_BORDER + end,
+                      inside_width, inside_height - end);
 
-    /* Restore the foreground color of the GC if we changed it above.  */
-    if (f->output_data.x->scroll_bar_foreground_pixel != -1)
       XSetForeground (FRAME_X_DISPLAY (f), gc,
                       FRAME_FOREGROUND_PIXEL (f));
-  }
+    }
 
-#ifdef HAVE_XDBE
-  if (!rebuild)
-    x_scroll_bar_end_update (FRAME_DISPLAY_INFO (f), bar);
-#endif
+  /* Restore the foreground color of the GC if we changed it above.  */
+  if (f->output_data.x->scroll_bar_foreground_pixel != -1)
+    XSetForeground (FRAME_X_DISPLAY (f), gc,
+                    FRAME_FOREGROUND_PIXEL (f));
 
   unblock_input ();
 }
@@ -14912,11 +14884,6 @@ x_scroll_bar_remove (struct scroll_bar *bar)
   XtDestroyWidget (SCROLL_BAR_X_WIDGET (FRAME_X_DISPLAY (f), bar));
 #endif /* not USE_GTK */
 #else
-#ifdef HAVE_XDBE
-  if (bar->x_window != bar->x_drawable)
-    XdbeDeallocateBackBufferName (FRAME_X_DISPLAY (f),
-                                  bar->x_drawable);
-#endif
   XDestroyWindow (FRAME_X_DISPLAY (f), bar->x_window);
 #endif
 
@@ -14962,6 +14929,12 @@ XTset_vertical_scroll_bar (struct window *w, int portion, int whole, int positio
         }
 
       bar = x_scroll_bar_create (w, top, left, width, max (height, 1), false);
+#ifdef USE_TOOKIT_SCROLL_BARS
+      /* Since non-toolkit scroll bars don't display their contents to
+         a dedicated window, no expose event will be generated.
+         Redraw the scroll bar manually.  */
+      x_scroll_bar_redraw (bar);
+#endif
     }
   else
     {
@@ -15021,6 +14994,11 @@ XTset_vertical_scroll_bar (struct window *w, int portion, int whole, int positio
       bar->width = width;
       bar->height = height;
 
+#ifndef USE_TOOLKIT_SCROLL_BARS
+      /* Redraw the scroll bar.  */
+      x_scroll_bar_redraw (bar);
+#endif
+
       unblock_input ();
     }
 
@@ -15328,60 +15306,84 @@ XTjudge_scroll_bars (struct frame *f)
 
 
 #ifndef USE_TOOLKIT_SCROLL_BARS
-/* Handle an Expose or GraphicsExpose event on a scroll bar.  This
-   is a no-op when using toolkit scroll bars.
-
-   This may be called from a signal handler, so we have to ignore GC
-   mark bits.  */
+/* Handle exposure event EVENT generated for F, by redrawing all
+   intersecting scroll bars.  */
 
 static void
-x_scroll_bar_expose (struct scroll_bar *bar, const XEvent *event)
+x_scroll_bar_handle_exposure (struct frame *f, XEvent *event)
 {
-#ifndef HAVE_XDBE
-  Window w = bar->x_window;
-#else
-  Drawable w = bar->x_drawable;
   int x, y, width, height;
+  XRectangle rect, scroll_bar_rect, intersection;
+  Lisp_Object bar, condemned;
+  struct scroll_bar *b;
 
-  if (event->type == Expose)
+  if (event->type == GraphicsExpose)
+    {
+      x = event->xgraphicsexpose.x;
+      y = event->xgraphicsexpose.y;
+      width = event->xgraphicsexpose.width;
+      height = event->xgraphicsexpose.height;
+    }
+  else
     {
       x = event->xexpose.x;
       y = event->xexpose.y;
       width = event->xexpose.width;
       height = event->xexpose.height;
     }
-  else
+
+  rect.x = x;
+  rect.y = y;
+  rect.width = width;
+  rect.height = height;
+
+  /* Scan this frame's scroll bar list for intersecting scroll
+     bars.  */
+  condemned = FRAME_CONDEMNED_SCROLL_BARS (f);
+  for (bar = FRAME_SCROLL_BARS (f);
+       /* This trick allows us to search both the ordinary and
+          condemned scroll bar lists with one loop.  */
+       !NILP (bar) || (bar = condemned,
+                       condemned = Qnil,
+                       !NILP (bar));
+       bar = XSCROLL_BAR (bar)->next)
     {
-      x = event->xgraphicsexpose.x;
-      y = event->xgraphicsexpose.y;
-      width = event->xgraphicsexpose.width;
-      height = event->xgraphicsexpose.height;
+      b = XSCROLL_BAR (bar);
+
+      scroll_bar_rect.x = b->left;
+      scroll_bar_rect.y = b->top;
+      scroll_bar_rect.width = b->width;
+      scroll_bar_rect.height = b->height;
+
+      if (gui_intersect_rectangles (&rect,
+                                    &scroll_bar_rect,
+                                    &intersection))
+        x_scroll_bar_redraw (b);
     }
-#endif
+}
+
+/* Redraw the scroll bar BAR.  Draw its border and set its thumb.
+   This is usually called from x_clear_frame, but is also used to
+   handle exposure events that overlap scroll bars.  */
 
+static void
+x_scroll_bar_redraw (struct scroll_bar *bar)
+{
   struct frame *f = XFRAME (WINDOW_FRAME (XWINDOW (bar->window)));
   GC gc = f->output_data.x->normal_gc;
 
-  block_input ();
-
-#ifdef HAVE_XDBE
-  if (w != bar->x_window)
-    {
-      if (f->output_data.x->scroll_bar_background_pixel != -1)
-        XSetForeground (FRAME_X_DISPLAY (f), gc,
-                        f->output_data.x->scroll_bar_background_pixel);
-      else
-        XSetForeground (FRAME_X_DISPLAY (f), gc,
-                        FRAME_BACKGROUND_PIXEL (f));
+  if (f->output_data.x->scroll_bar_background_pixel != -1)
+    XSetForeground (FRAME_X_DISPLAY (f), gc,
+                    f->output_data.x->scroll_bar_background_pixel);
+  else
+    XSetForeground (FRAME_X_DISPLAY (f), gc,
+                    FRAME_BACKGROUND_PIXEL (f));
 
-      XFillRectangle (FRAME_X_DISPLAY (f),
-                      bar->x_drawable,
-                      gc, x, y, width, height);
+  XFillRectangle (FRAME_X_DISPLAY (f), FRAME_X_DRAWABLE (f), gc,
+                  bar->left, bar->top, bar->width, bar->height);
 
-      XSetForeground (FRAME_X_DISPLAY (f), gc,
-                      FRAME_FOREGROUND_PIXEL (f));
-    }
-#endif
+  XSetForeground (FRAME_X_DISPLAY (f), gc,
+                  FRAME_FOREGROUND_PIXEL (f));
 
   x_scroll_bar_set_handle (bar, bar->start, bar->end, true);
 
@@ -15391,27 +15393,13 @@ x_scroll_bar_expose (struct scroll_bar *bar, const XEvent *event)
                     f->output_data.x->scroll_bar_foreground_pixel);
 
   /* Draw a one-pixel border just inside the edges of the scroll bar.  */
-  XDrawRectangle (FRAME_X_DISPLAY (f), w, gc,
-                  /* x, y, width, height */
-                  0, 0, bar->width - 1, bar->height - 1);
-
-  /* XDrawPoint (FRAME_X_DISPLAY (f), w, gc,
-                 bar->width - 1, bar->height - 1);
-
-     This code is no longer required since the normal GC now uses the
-     regular line width.  */
+  XDrawRectangle (FRAME_X_DISPLAY (f), FRAME_X_DRAWABLE (f), gc,
+                  bar->left, bar->top, bar->width - 1, bar->height - 1);
 
   /* Restore the foreground color of the GC if we changed it above.  */
   if (f->output_data.x->scroll_bar_foreground_pixel != -1)
     XSetForeground (FRAME_X_DISPLAY (f), gc,
                     FRAME_FOREGROUND_PIXEL (f));
-
-#ifdef HAVE_XDBE
-  x_scroll_bar_end_update (FRAME_DISPLAY_INFO (f), bar);
-#endif
-
-   unblock_input ();
-
 }
 #endif /* not USE_TOOLKIT_SCROLL_BARS */
 
@@ -15552,24 +15540,6 @@ x_scroll_bar_note_movement (struct scroll_bar *bar,
     }
 }
 
-#ifdef HAVE_XDBE
-static void
-x_scroll_bar_end_update (struct x_display_info *dpyinfo,
-                         struct scroll_bar *bar)
-{
-  XdbeSwapInfo swap_info;
-
-  /* This means the scroll bar is double-buffered.  */
-  if (bar->x_drawable != bar->x_window)
-    {
-      memset (&swap_info, 0, sizeof swap_info);
-      swap_info.swap_window = bar->x_window;
-      swap_info.swap_action = XdbeCopied;
-      XdbeSwapBuffers (dpyinfo->display, &swap_info, 1);
-    }
-}
-#endif
-
 #endif /* !USE_TOOLKIT_SCROLL_BARS */
 
 /* Return information to the user about the current position of the mouse
@@ -15710,17 +15680,15 @@ x_horizontal_scroll_bar_report_motion (struct frame **fp, Lisp_Object *bar_windo
 }
 
 
-/* The screen has been cleared so we may have changed foreground or
-   background colors, and the scroll bars may need to be redrawn.
-   Clear out the scroll bars, and ask for expose events, so we can
-   redraw them.  */
+/* The screen has been cleared and foreground or background colors may
+   have changed, so the scroll bars need to be redrawn.  Clear the
+   scroll bars and redraw them.  */
 
 static void
 x_scroll_bar_clear (struct frame *f)
 {
 #ifndef USE_TOOLKIT_SCROLL_BARS
-  Lisp_Object bar;
-#ifdef HAVE_XDBE
+  Lisp_Object bar, condemned;
   GC gc = f->output_data.x->normal_gc;
 
   if (f->output_data.x->scroll_bar_background_pixel != -1)
@@ -15729,35 +15697,25 @@ x_scroll_bar_clear (struct frame *f)
   else
     XSetForeground (FRAME_X_DISPLAY (f), gc,
                     FRAME_BACKGROUND_PIXEL (f));
-#endif
 
   /* We can have scroll bars even if this is 0,
      if we just turned off scroll bar mode.
      But in that case we should not clear them.  */
   if (FRAME_HAS_VERTICAL_SCROLL_BARS (f))
-    for (bar = FRAME_SCROLL_BARS (f); VECTORP (bar);
-         bar = XSCROLL_BAR (bar)->next)
-      {
-#ifdef HAVE_XDBE
-        if (XSCROLL_BAR (bar)->x_window
-            == XSCROLL_BAR (bar)->x_drawable)
-#endif
-          XClearArea (FRAME_X_DISPLAY (f),
-                      XSCROLL_BAR (bar)->x_window,
-                      0, 0, 0, 0, True);
-#ifdef HAVE_XDBE
-        else
-          XFillRectangle (FRAME_X_DISPLAY (f),
-                          XSCROLL_BAR (bar)->x_drawable,
-                          gc, 0, 0, XSCROLL_BAR (bar)->width,
-                          XSCROLL_BAR (bar)->height);
-#endif
-      }
+    {
+      condemned = FRAME_CONDEMNED_SCROLL_BARS (f);
+      for (bar = FRAME_SCROLL_BARS (f);
+           /* This trick allows us to search both the ordinary and
+              condemned scroll bar lists with one loop.  */
+           !NILP (bar) || (bar = condemned,
+                           condemned = Qnil,
+                           !NILP (bar));
+           bar = XSCROLL_BAR (bar)->next)
+        x_scroll_bar_redraw (XSCROLL_BAR (bar));
+    }
 
-#ifdef HAVE_XDBE
   XSetForeground (FRAME_X_DISPLAY (f), gc,
                   FRAME_FOREGROUND_PIXEL (f));
-#endif
 #endif /* not USE_TOOLKIT_SCROLL_BARS */
 }
 
@@ -17643,7 +17601,7 @@ handle_one_xevent (struct x_display_info *dpyinfo,
 
           if (!FRAME_GARBAGED_P (f))
             {
-#ifdef USE_X_TOOLKIT
+#if defined USE_X_TOOLKIT && defined USE_TOOLKIT_SCROLL_BARS
               if (f->output_data.x->edit_widget)
                 /* The widget's expose proc will be run in this
                    case.  */
@@ -17658,10 +17616,17 @@ handle_one_xevent (struct x_display_info *dpyinfo,
 #endif
               expose_frame (f, event->xexpose.x, event->xexpose.y,
                             event->xexpose.width, event->xexpose.height);
+#ifndef USE_TOOLKIT_SCROLL_BARS
+              x_scroll_bar_handle_exposure (f, (XEvent *) event);
+#endif
 #ifdef USE_GTK
               x_clear_under_internal_border (f);
 #endif
             }
+#ifndef USE_TOOLKIT_SCROLL_BARS
+          else
+            x_scroll_bar_handle_exposure (f, (XEvent *) event);
+#endif
 
 #ifdef HAVE_XDBE
           if (!FRAME_GARBAGED_P (f))
@@ -17670,9 +17635,6 @@ handle_one_xevent (struct x_display_info *dpyinfo,
         }
       else
         {
-#ifndef USE_TOOLKIT_SCROLL_BARS
-          struct scroll_bar *bar;
-#endif
 #if defined USE_LUCID
           /* Submenus of the Lucid menu bar aren't widgets
              themselves, so there's no way to dispatch events
@@ -17684,20 +17646,8 @@ handle_one_xevent (struct x_display_info *dpyinfo,
           }
 #endif /* USE_LUCID */
 
-#ifdef USE_TOOLKIT_SCROLL_BARS
           /* Dispatch event to the widget.  */
           goto OTHER;
-#else /* not USE_TOOLKIT_SCROLL_BARS */
-          bar = x_window_to_scroll_bar (event->xexpose.display,
-                                        event->xexpose.window, 2);
-
-          if (bar)
-            x_scroll_bar_expose (bar, event);
-#ifdef USE_X_TOOLKIT
-          else
-            goto OTHER;
-#endif /* USE_X_TOOLKIT */
-#endif /* not USE_TOOLKIT_SCROLL_BARS */
         }
       break;
 
@@ -17711,6 +17661,9 @@ handle_one_xevent (struct x_display_info *dpyinfo,
                         event->xgraphicsexpose.y,
                         event->xgraphicsexpose.width,
                         event->xgraphicsexpose.height);
+#ifndef USE_TOOLKIT_SCROLL_BARS
+          x_scroll_bar_handle_exposure (f, (XEvent *) event);
+#endif
 #ifdef USE_GTK
           x_clear_under_internal_border (f);
 #endif
@@ -17718,16 +17671,6 @@ handle_one_xevent (struct x_display_info *dpyinfo,
           show_back_buffer (f);
 #endif
         }
-#ifndef USE_TOOLKIT_SCROLL_BARS
-      struct scroll_bar *bar
-        = x_window_to_scroll_bar (dpyinfo->display,
-                                  /* Hopefully this is just a window,
-                                     not the back buffer.  */
-                                  event->xgraphicsexpose.drawable, 2);
-
-      if (bar)
-        x_scroll_bar_expose (bar, event);
-#endif
 #ifdef USE_X_TOOLKIT
       else
         goto OTHER;
diff --git a/src/xterm.h b/src/xterm.h
index 2e3d0950d91..2b8a2e5da49 100644
--- a/src/xterm.h
+++ b/src/xterm.h
@@ -1282,11 +1282,6 @@ struct scroll_bar
   /* The X window representing this scroll bar.  */
   Window x_window;
 
-#if defined HAVE_XDBE && !defined USE_TOOLKIT_SCROLL_BARS
-  /* The X drawable representing this scroll bar.  */
-  Drawable x_drawable;
-#endif
-
   /* The position and size of the scroll bar in pixels, relative to the
      frame.  */
   int top, left, width, height;