How to remove Alt+F7 window moving hot-key in Xubuntu?

I'd like to use Alt+F7 to search for files in Double Commander.

But when I press Alt+F7 - the hotkey is intercepted and I am offered to move the window.
Settings - Settings manager - Keyboard - Application shortcuts doesn't show Alt+F7 to be bound to anything.

Where can I undefine Alt+F7 hot key then?


Settings - Window Manager - Keyboard

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Double Click the short cut field and choose the key-combination you want

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