Texture Painting: Blocking around brush strokes (Blender 2.73)

Hi,
I’m learning how to use texture painting with my current model and have run into an odd problem. I’m using the face selection masking option. When I apply the brush stroke in the 3D Editor, the image in the UV Editor shows a rectangular black square around the brush stroke as shown in the image below:

http://i1188.photobucket.com/albums/z410/casper131/Ashampoo_Snap_20150121_22h27m33s_001__zps07418635.jpg

But if I do another brush stroke and undo (Ctrl Z) the UV Editor view corrects itself.

http://i1188.photobucket.com/albums/z410/casper131/Ashampoo_Snap_20150121_22h28m07s_002__zpscf52cbc7.jpg

At one stage I thought the UV mapping may be corrupted so I was remapping parts of the model. This seemed to fix it but then a remapped mesh had the same problem so perhaps the mapping was not at fault.

The problem is intermittent but happens more often than not.

Any ideas on what may be causing it. My workaround is the undo trick but that’s hardly satisfactory.

TIA

Paul

Attachments


Problem solved. User Preferences -> System -> Images Draw Method should be GLSL. (or for at least for what I was doing)

Tks to Luminokan for the answer.