I have also noticed this as wellon KDE. I don’t need to alt-tab usually because I have 2 large screens, however if I have one window focused and do a CTRL+Click for example in another, sometimes the mouse pointer will become a + and allow me to drag a multi select square. When it gets stuck in this mode, I can’t activate any modules, chat, or anything until I go back to the offending window, focus it, and CTRL+Click on it.