When using some tools such as the Color Anchors tool, the whole pano is turned opaque white and only the image I'm hovering over is normal (let's call this 'hover mode'). What should happen when I move the cursor off the images is that the whole preview is shown normally, without the opaque white. The bug is that most often when I move the mouse cursor off the preview it remains in hover mode. To get it to show properly, I have to move the mouse cursor back over the preview near any edge and then slowly drag it away. This seems to trigger the preview change back to normal. This only works on the left, bottom and right edges, not the top. I have marked this trigger area in green on the screenshot.

Gentoo Linux, nvidia-drivers 30*.* (currently 304.64)