Scratch

When I export a sprite from Scratch and then import it again later, all the orange variable blocks like "set variable" and "change variable" no longer work. Also clicking on any of the variable reporters shows that they all equal zero. If I click on the "set variable" blocks that were in the sprite when it was imported, they don't do anything and just stay highlighted as if the program doesn't recognise them. I can make them work again by replacing all the blocks with fresh ones but this takes a lot of time. This might only be a problem with my computer but I thought I should post it just in case it isn't.