In Delphi I got used to pressing F12 whenever my program becomes irresponsive to see what the Main thread is doing, mainly for stack trace but sometimes also local vars.
Now I am playing around with SharpDevelop and can't see anything quite like that. Is it possible at all?
There is not pre-defined keyboard shortcut in SharpDevelop for debug break. It is available from the Debug menu by selecting Debug - Break. You can also press the pause button in the main toolbar.
If you want a keyboard shortcut then you would need to edit the ICSharpCode.SharpDevelop.addin file and add a shortcut to the Break menu. Below shows the Break menu item, without a keyboard shortcut, and the Continue menu item which has F5 as its shortcut.
So you can add a new shortcut attribute for the Break menu item if you want to by editing the ICSharpCode.SharpDevelop.addin file.