Ok, try this:
Create a simple triangle mesh object (like maybe a sphere that you convert to a triangle mesh).
Open it with the mesh editor.
Make sure you are in "move/scale/rotate" selection mode.
Hold SHIFT for uniform scaling.
Use the scale manipulator to scale a portion of the mesh.
If you scale in, you are "stuck" scaling in, any movement continues to scale in.
The same is true if you scale out.
It also seems to scale abnormally fast.
This does not happen in the Polymesh editor.
Hope this bug can be fixed :)