OK Adobe Photoshop CS 4 is locking up an XP machine when doing a brush stroke on a mask/alpha channel. Eventually it becomes responsive after a few min. Now it's weird as all that the image has is 5 adjustment layers, and Ps CS 4 works fine with other images from the session with more layers. The image is also fine on another machine (Vista).
Has anyone else experienced this? It's just one image that Ps hates, even after a reboot.

