[NSCursor +setHiddenUntilMouseMoves:]

[Adrian Robert]

Hi,

While working on Emacs I found that [NSCursor 
+setHiddenUntilMouseMoves:] wasn't working for me: whenever a key was 
typed, the mouse reappeared as if the mouse had moved.  I traced this 
to the following: when Emacs receives a key event, it halts GNUstep's 
event loop to allow Emacs's own event loop to continue and process it.  
In NSApplication, this causes, at line 1497 in -stop:, a 'null_event' 
to be posted to the DPSServer, supposedly to "allow one more pass 
through the loop".  The problem is, later on during this one more pass, 
line 1664 misinterprets this as a valid event of type NSLeftMouseDown 
(which happens to be zero in the NSEventType enumeration), and calls 
[NSCursor -setHiddenUntilMouseMoves: NO].

Two possible fixes:

   1) Do not post null_event on -stop:.  I commented this line out with 
no
      ill effects, though obviously more testing is needed than that.

   2) Delay the updating of [NSCursor setHiddenUntilMouseMoves:] until
      somewhere around line 1179, i.e., AFTER the initial masked event
      retrieval from the DPSServer where was posted.  Here, the 
'null_event'
      is already filtered out by an 'if'.

#2 is the least invasive change, however it would be nice to know the 
reasons for posting 'null_event' on -stop: and whether it is still 
needed.  Also, if delaying showing the mouse this long is undesirable, 
detection for 'null_event' could be inserted into the method at line 
1664.

Any thoughts?