Here's a somewhat contrived test case:
- Open your inventory and alt-click an empty slot to start setting a filter.
- Control-alt-click the ground to post a location tag to chat.
- Click an item in the "Select filter" dialog which overlaps with the rich text for the location. (Depending on screen size and UI scale, you might have to move the dialog to make this happen.)
- Notice that the game behaves as if you had clicked the location without the dialog being in the way.
This behavior affects other select-a-thing dialogs as well (like selecting an icon for a map tag, or a signal for a combinator), and may affect other dialogs as well -- I haven't tested this extensively.