Normally when you click on a tab that opens a pop-up list (for example selection routing targets etc), this list opens and you get to click any of the items.
However, if you click on the list and the list happens to open under your mouse cursor, so that when the list opens, your cursor is already on one of the menu items, releasing the button selects this item.
The result is that when you click on such list in such spot, you see the list just flash and you accidentally selected one item that happened to be on the mouse.
No matter if there's a menu item under the cursor, it shouldn't be selected on mouse-up event. (sorry I'm using a javascript term, meaning the release of the mouse button)
[4629] Pop-up lists that react to mouse-up -event
[4629] Pop-up lists that react to mouse-up -event
Juhana Lehtiniemi - Film composer with Ableton Live