Debugging and the GUI Editor; Qt help needed

[John W. Eaton]

I checked in a series of changes that improve the way the GUI editor 
works with Octave's debugger.  The editor will now display breakpoints 
set with the mouse or with the dbstop function, and it will place a 
pointer at the point where execution is currently stopped.  Clearing 
breakpoints with the mouse or with dbclear removes the markers from the 
editor tab.  Files are opened automatically as needed when stepping into 
functions.

It's mostly working, but I've noticed a few quirks.  First, the debugger 
is not returning to parent functions properly.  I don't think this has 
anything to do with the editor, but is likely a problem that needs to be 
fixed in the debugger/evaluator.

Sometimes, clicking in the editor margin to insert a breakpoint will 
result in two markers being inserted in the margin for one click.  Then 
dbclear won't always clear all of these markers.

The cursor is often displayed at the bottom of the window.  It might be 
nice to automatically recenter.  Does someone know how to do that with 
QScintilla?  I looked, but couldn't see how to do it easily.

When a breakpoint is set, the focus moves to the editor window.  I find 
that I forget that the focus has shifted and start typing debugging 
commands into the editor instead of the command window.  Maybe we should 
display the window but not change the focus?

If the editor widget is docked when dbstop is used to set a breakpoint, 
it remains docked and hidden.  I think this will not be very helpful for 
new users, and that it would be better to pop up the editor window so 
that the command window and the editor window are both visible.  I'm not 
sure how to do that.  Can someone with Qt expertise help with that?

It would be helpful if people could test these new features.  There is 
no need to report the problems I've listed above, but if you find other 
things that don't work correctly, let me know.  Or if you'd just like to 
say, "Wow, these new features look awesome!" that would be fine too.

jwe