Tree creator bug?

The Unity 3D tree creator (version 3.3) has a functionality through which certain numeric data can be entered either by typing in the number or by dragging the cursor left/right over the input box as a slider. For me, these input boxes appear to have gotten stuck in the latter mode, effectively preventing me from entering a number myself. Restarting Unity does not seem to solve the problem. As far as I can see, only the branch nodes of the tree are affected; the input boxes on the leaves and the base node still function properly.

Is there any method I am overlooking to toggle the slider functionality off/on, or is this (as I presume) unwanted behavior?