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Archive for June, 2009

XP – MouseMove Event fired repeatedly by File Search Animation

This is a bug with windows XP, caused by the dog animation, that appears by default when you perform a file search.

I had a standard Windows Form Application with a ListView control on it. I setup a MouseMove event on the control.

The normal way this operates is as you move the mouse over the control the MouseMove event fires. Stop moving the mouse and the event does not fire. Seems simple.

Today however I noticed that the MouseMove event was firing repeatedly, even when the mouse was not moving!!

I wrote a very simple windows form test app with only this code and put debug logging on the MouseMove event and found that it was not happening on some other machines.

On the machine where things were going pear shaped I started closing applications until the only things open were some folders that I had been using, and the test app. It was still doing it. I closed all the folders and the MouseMove event stopped firing.

I tracked it down to the following:

  1. Open an file explorer window –> no problem
  2. Press Ctrl + F (find) (the dog annimation apears) –> problem the MouseMove event fires repeatedly even when the mouse is stationary over the control with the MouseMove event
  3. Go “Change Preferences”, and choose “Without an animated screen character”, the dog buggers off and –> No problem.

The animation must be taking control of the mouse and when it gives it back to my form it causes the mouse move event to fire.

Thats 1.5 hours of my life I will never get back.

Thanks Microsoft 😛

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Categories: Windows Forms