Always on top of a full-screen app?

An editor (notepadqq) is opened in a full screen mode. I need a calculator app (SpeedCrunch) to be always visible on top of the editor in the same workspace. When I set the calc to be ‘always on top’ via its title bar menu – it disappears anyway when I focus on the editor window. Is there a way to resolve that? Thanks a lot.

And one more thing – the title bar menu always pops up upon a right click on a freshly opened window’s title bar, but if I tick ‘always on top’ and want to open title bar menu again – it doesn’t pop up anymore upon the first click. It needs 20-30 clicks on a title bar and then, sometimes, it pops up again…