Winform blinks when Java application is activated.

[Guest]

Hello,

We are having an unusual issue with a .NET 1.1 Winforms application. There
is one particular Winform within the application that blinks, or quickly
diappears and reappears on the screen, when a Java application is maximized
and sharing the screen with the Winform. It almost looks like a timer, with
each second causing the Winform to quickly disappear and reappear. This only
occurs when the Java application is also sharing the desktop screen with the
Winform. When the Java application is minimized, the Winform stops blinking.

What is interesting is that this is one of three Winforms that are open and
visible from the same Winform assembly, but only one has the blinking issue.
So far we are able to give the users a temporary fix by changing the refresh
rate on their displays to anything, then back to their original refresh rate,
and the problem then completely goes away until the PC is rebooted or logged
out.

I've done some searches, and have found that there are bugs in the
transparency of Winforms, and that setting the Transparency Key property to a
Color usually resolves the issue. I tired this, and it didn't work.

I'm going to try and create a project with just this Winform, to see if I
can recreate the issue. Please let me know if there are any known issues
concerning this, whether there is already a resolution to this problem.

Thanks,

Dave

 

[Guest]

I have been able to scale down the application to just the Winform, and a
supporting class that is having the issue. I can send this for analysis if
necessary.

Thanks,

Dave

 

[Guest]

It appears I might have a fix for this, although I'm still testing it, and
not sure what I've really changed to make the fix. The WinForm originally
did not have it's Transparent Key property set to anything. I attempted to
set it to a color after reading the following article, which suggests at the
end that there is an inherit flaw with setting a WinForm to a layered window:

http://www.codeproject.com/csharp/notanotherformfader.asp?df=100&forumid=207201&exp=0&select=1193830

After playing a little bit with my scaled down example, I tried to set the
Transparent Key back to an empty value, or nothing. I found this quite
difficult, because the properites window in VS 2003 didn't really give me
this option in the color pallete, when attempting to change the property
value. Once you select a color from the palette, the property value is set
to a color name like 'White', or a set of RGB values, like '0, 192, 0'. I
was able to remove the value from the properties window, which effectively
set this value back to nothing (I'm guessing). When this occurred, I was
able to resolve the issue. When the Transparent Key is set to any color, the
blinking occurs.

I've checked this code into our source code repository, and do not see any
differences relating to the property setting. So, I'm leary as to whether
anything was really changed, and whether this has resolved the issue
perminently or not. I'm planning on pulling the change onto another
developers machine to test it out and see if the issue was resolve.

At this point, it does appear to be related to the Transparent Key property
value.

 

[Guest]

I've tested this on my machine, and a couple of others. I can not
consistently reproduce the issue by assigning, or removing assignment of the
Transparent Key. It appears the issue is resolved at the moment on my
machine, but I'm not confident as to whether this will be fixed on the
several 100 production PC's that this application is deployed too. If there
is any additional information concerning this issue, please let me know.

Thanks,

Dave