I have encountered what I shall presume is a bug: setting
$RecursionLimit repeatably crashes the Mathematica 10 kernel:
$RecursionLimit = 50 (* kernel crash *)
$RecursionLimit = 20 produces a malformed Suggestions Bar containing text code starting with:
Manipulate`Dump`eDynamicModule[ . . .
I am running version 10.0.0.0 on Windows 7. Please report behavior on your system.