Please tell me that things like indicator applet complete will be configurable in future LTS

[Alarik]

First - to take a timed screen-shot you can see tutorial on how to capture screen when you've got some menues open and print-screen won't register:

Getting screen snapshot showing context menus from right-click

I was a long time unable to get a screen snapshot showing pull-down menus and other similar things. I discovered that the MATE panel app "Take Screenshot" has a "countdown timer" (a.k.a. "Grab after a delay of ...") before taking a screenshot, so I now use that. Start the countdown, by using settings like those shown below, then do the menu or right-click to show the desired context-menu/display and wait for the snapshot to pop up with the "save" window. You can adjust the dela…

Second, if you RIGHT-CLICK - on any applet added to panel you should see this:

And when you click "Lock to panel" - it should unlock it and you will be able to press "Remove from panel"