Here you can link to screenshots and demos etc. of programs made using BBC BASIC
I think you misunderstood my point. The flashing caret should indicate that entry into the 'text box' is accepted, and if it is I would say everything is working correctly. That a different window (which doesn't currently have the input focus) doesn't receive any keyboard input - even if that window is waiting in GET - is as it should be. After all it's entirely possible that two or more windows may be simultaneously running programs which are all waiting in GET; the way Windows (or any other multi-tasking windowing system) has to work is that only one - or none - sees keystrokes.
My posts are moderated; if you are seeing this it has already been approved. If you have a comment about the style or tone of the message please report it to the moderators by clicking the exclamation mark icon rather than complaining on the public forum.