runouw.com

I'm sure clearing browser history doesn't conflict with your cookies by default (You can make it so it clears cookies,too.).
Such problem is mostly caused by having limited cookie limit on a site (You can configure it in the saving interface in the Level Designer). The default cookie limit is 100 MB,I suggest you to make it infinite,so you don't have to worry about going over limit.

I've tried to make this thing larger once (because I've thought it would refer to the code size), but then the LDer screwed up and was far less performant so I've changed it back. Saving by code is still what everyone should do.