UI: support an 'active default' button for pop-ups

Use this for the save confirmation dialog so it has a default action
when pressing enter which draws with a highlight so it's clear what the
default action is (the dialog was just closing before).

Resolves T57686

1 files changed, 8 insertions, 1 deletions

diff --git a/source/blender/editors/interface/interface_handlers.c b/source/blender/editors/interface/interface_handlers.c
index d1294dcfed2..c388ed40851 100644
--- a/source/blender/editors/interface/interface_handlers.c
+++ b/source/blender/editors/interface/interface_handlers.c
@@ -9241,9 +9241,16 @@ static int ui_handle_menu_event(
 				menu->menuretval = UI_RETURN_CANCEL;
 			}
 			else if (ELEM(event->type, RETKEY, PADENTER) && event->val == KM_PRESS) {
+				uiBut *but_active = ui_region_find_first_but_test_flag(ar, UI_BUT_ACTIVE_DEFAULT, UI_HIDDEN);
+				if (but_active != NULL) {
+					ui_handle_button_activate(C, ar, but_active, BUTTON_ACTIVATE);
+					/* Get again below just incase it's disabled for eg. */
+				}
+				but_active = ui_region_find_active_but(ar);
+
 				/* enter will always close this block, we let the event
 				 * get handled by the button if it is activated, otherwise we cancel */
-				if (!ui_region_find_active_but(ar)) {
+				if (but_active == NULL) {
 					menu->menuretval = UI_RETURN_CANCEL | UI_RETURN_POPUP_OK;
 				}
 			}