Sometimes after running a query I am unable to type anything into the SQL Editor window. I can still see the screen and my query. I can click on buttons in the toolbars and other windows and system applications work fine -- I am just unable to alter any of the queries.
I use Shift+F9 to execute the query.
Accidentally pressing Shift-F10 or other debugging shortcut keys will send the Editor into debug mode, locking the editor window. A black arrow will appear in the left margin and the debug icons toolbar will be enabled.
Click the cancel button to end the debug session and the editor will be editable again.