in Gtk4 GtkComboBox menus only open after releasing the mouse button. This disables the click, drag, release interaction to select menu items that has been available since forever(?) and dates back to the earliest GUIs such as the original macintosh. While I can see that this is consistent with how MenuButtons work, I believe that this somewhat of a usability regression as this requires an additional mouse click.
The reason for buttons only getting activated on the mouse up event is to give the user a chance to change their mind after they pressed a button by moving the cursor outside of the button. For MenuButtons however, this behavior however doesn’t make much sense as activating the button only opens the menu and doesn’t trigger any action. Would there be anything wrong with opening the menu the moment the button is pressed and activating menu items once the mouse button has been released?
This could be step towards re-enabling the click, drag, release interactions for menus and comboxes in gtk4.