Fixed bug where switching workspaces crashed gnome shell (sporatic and difficult to duplicate)
Fixed bug where edge of dock that supposed to be visible in slid out state was not when thumbnails resized.

Details:
Sometimes thumbnailsBox actor is wider than thumbnailsBox background. This happens when thumbnail count grows and thumbnails have to be resized. Solution was to manually set thumbnailsBox actor width equal to background width.
Fixed bug where turning on/off fixed mode in preferences didn't reset workspace apps in caption