Scratch FixVariableDisplayIssue
There is a bug within all offical versions of Scratch on all platforms that maninfests itself badly on low power devices such as the RPi.
MathsWhizz from the Scratch forums has developed a solution which only just involves a few small changes to the Scratch.image. A modified image for use on Raspbian based systems is available to download here.
The instructions for installing this slightly modified image will be posted shortly.