Fix mysterious crash on tooltips

This was a hard to reproduce bug, but it happens often enough.
Basically the tooltip of the active tool was been invoked when
context had no valid ScrArea which would lead to a crash.

We now just return no tooltip in these cases.

1 files changed, 5 insertions, 0 deletions

diff --git a/source/blender/editors/interface/interface_region_tooltip.c b/source/blender/editors/interface/interface_region_tooltip.c
index 449e783b03e..d016deb26cb 100644
--- a/source/blender/editors/interface/interface_region_tooltip.c
+++ b/source/blender/editors/interface/interface_region_tooltip.c
@@ -901,6 +901,11 @@ ARegion *UI_tooltip_create_from_button(bContext *C, ARegion *butregion, uiBut *b
 			RNA_string_get(but->opptr, "keymap", keymap);
 			if (keymap[0]) {
 				ScrArea *sa = CTX_wm_area(C);
+				/* It happens in rare cases, for tooltips originated from the toolbar.
+				 * It is hard to reproduce, but it happens when the mouse is nowhere near the actual tool. */
+				if (sa == NULL) {
+					return NULL;
+				}
 				wmKeyMap *km = WM_keymap_find_all(C, keymap, sa->spacetype, RGN_TYPE_WINDOW);
 				if (km != NULL) {
 					data = ui_tooltip_data_from_keymap(C, km);