Just installed Tabbles 1.3.5. I attempted to add a wallpaper. When I added the wallpaper it needed to be resized. However, I noticed that all the Tabbles icons were reduced to an unrecognized size on the wallpaper. I then resized the wallpaper to fit within the Tabbles window. This worked successfully. I then locked the wallpaper. However, the Tabbles icons in the window remainded at an unrecognizable size. Using my cursor I attempted to highlight the icons in the hope of making them larger by holding down the right mouse button. When I did so and moved the mouse the wallpaper moved (I thought it was locked and it shows locked!). When I used the resize tools (Bar and round button) it made the icons on the screen larger. However, it also greatly enlarged the wallpaper so that the window looked as if it were a single color instead of wallpaper. I’m going to remove the wallpaper for now.
Hope this helps!