int width = FRAME_PIXEL_WIDTH (f);
int y = nlines * FRAME_LINE_HEIGHT (f);
- BLOCK_INPUT;
- x_clear_area (FRAME_X_DISPLAY (f), FRAME_X_WINDOW (f),
- 0, y, width, height, False);
- UNBLOCK_INPUT;
+ /* height can be zero here. */
+ if (height > 0 && width > 0)
+ {
+ BLOCK_INPUT;
+ x_clear_area (FRAME_X_DISPLAY (f), FRAME_X_WINDOW (f),
+ 0, y, width, height, False);
+ UNBLOCK_INPUT;
+ }
if (WINDOWP (f->tool_bar_window))
clear_glyph_matrix (XWINDOW (f->tool_bar_window)->current_matrix);