Cancel minibuffer when clicking another window

Hi list,

When Emacs reads input in the minibuffer (i.e., with `read-from-minibuffer`
or `completing-read`, etc.) and you click some other window with the mouse,
that window is selected, but the minibuffer input isn't cancelled.

Is there a way to automatically cancel the minibuffer input when clicking
another window?

I've been trying with `mouse-leave-buffer-hook` and by adding advice before
`mouse-set-point`, with various functions (`keyboard-quit`,
`minibuffer-keyboard-quit`, `abort-minibuffers`, `abort-recursive-edit`),
but either nothing happens, or I get an error "not in a minibuffer"...

TIA

-- 
Joost Kremers
Life has its moments