It shouldn't need to be double clicked, I just left click it once and it opens.
What OS version ans avast program and version number are you using ?
Min is win10 21H2 (OS Build 19044 1466) latest patch Tuesday update and Avast Free 21.11.2500 (build 21.11.6809.528).
There have been some issues related to the tray icon, but this hasn't been mentioned. So I don't know if this is related to those issues (not being able to completely hide the tray icon).