Bitmap and threads

Hi All,

Can anyone shed any light on whats going on here?

I have a windows form, which loads a bitmap stored in:

Bitmap bOriginalImage;

I then create a clost

Bitmap backBuffer = bOriginalImage();

this backbuffer is then used in the paint method to display the image in a panel on the form.

I then want to do some analysis on the original file in another thread, as such:

ThreadStart starter = delegate { da.analyse(bOriginalImage); };
Thread t = new Thread(starter);

During the analysis (which takes a few minutes) everything is fine, until something happens to cause the panel to be repainted.

Then I get a runtime error:

System.InvalidOperationException was unhandled
Message="Bitmap region is already locked."

I don't know why, because I assumed that the painting and the analysis were being done on separate copies of the bitmap.

What am I missing?!

Thanks