For some time I have had windows task manager in a tools frame, i.e. with no menu nor visibility to the menu system. I could of course still control it via keyboard (shift tab and then key right of left for selecting the different sub-pages but it is still highly limiting) and not all the pull down menus have key shortcuts (at least not ones I know by heart).

It shows that I can just double click on the outline of the window, and hey presto – it’s there again!