Operating system and graphics card
Broken: (example: 2.69.7 4b206af, see splash screen)
Short description of error
The text editor lacks of the plus sign to open the Tool Shelf when you switch from let's say 3D view to text editor.
Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps
Open Blender. In 3D view switch to Text editor. Have a look for the plus sign that usually indicates that there is a tool shelf at the right or left side. It is missing.
When you open the tool shelf for one time, like with ctrl + t, and close it, then the plus sign will become visible.