I often edit some text in IntelliJ and use alt+tab to switch to the browser to test the (JSP) changes. Then I come back by pressing ALT+Tab again to continue editing the file. Most of the time the focus is not any more in the file edit part but on the main menu bar on the File sub menu. This is quite annoying because my work flow is interrupted most of the time. I can consistently reproduce this by pressing alt-tab several times. Make sure do the alt-tab switching / key pressing in different speed. It seems the focus-stealing only comes with a certain time of holding the keys. If you need more information please let me know. You're doing an awesome job with Intellij!