R GUI copy/save PDF drawing bug

Hello,

I have been going through the R GUI code trying to fix a specific
bug. I reported this a while ago and tried to fix it then but with no
luck:

https://stat.ethz.ch/pipermail/r-sig-mac/2006-March/002723.html

I've had another stab at it, and this is what I think is going on.
There is an NSTimer that fires every 0.5 s that calls showWorkingDir:
in RController.m. My guess is that when copy: is called in RQuartz.m
and the operation takes more than 0.5 s that the working directory
text field (WDirView) is being drawn on that view since the focus is
locked onto it. This depends on the relative positions and sizes of
the windows as well, which makes sense with the relative coordinate
systems.

You'll much more likely to see this on plots with a large amount of
data since they take more time to draw (relatively). This is very
typical for me so I see the problem all the time.

Here's my solution:

R.Controller.h

add instance:
NSMutableString *currentWorkingDirectory;

RController.m

in init add:
currentWorkingDirectory = [[NSMutableString string] retain];

Replace showWorkingDir with:

- (IBAction) showWorkingDir:(id)sender
{
	NSString *wd = [[NSFileManager defaultManager] currentDirectoryPath];
	if (!wd) wd = NLS(@"<deleted>");
	if (![currentWorkingDirectory isEqualToString:wd]) {
		[WDirView setStringValue: [wd stringByAbbreviatingWithTildeInPath]];
		[currentWorkingDirectory	 setString:wd];
	}
}

...and then to clean up, in dealloc add:
[currentWorkingDirectory release];

Note that it is unnecessary to call setEditable:. This is only used
to make the text field editable by the user which is never the case.

This function only attempts to update the view if the current
directory has actually changed which will never happen in the middle
of a copy/paste/save operation. Well, I suppose it will if the
working directory is somehow deleted while someone copies or saves,
but I'm willing to live with that.

Finally, is the timer in place only to see if the folder has been
removed from underneath R? If so, it might be cleaner to set
something up to notify us when a particular directory (e.g. the
current working directory) has been removed. There is a class called
DRFileNotificationSubscription described here that does exactly that.

http://www.cocoadev.com/index.pl?FileSystemNotifications

If you'd like, I can code it up and test it, but I wanted to ask if
there was another purpose for the timer before spending the time on  
it.

Cheers,

Demitri