Found a little issue in 1.0.13.
If you have two plugins with the same name, even if one is disabled, you can not save changes.
When i've tried to set the name of my "Configuration Chunk" in ManagerManager:
There is already a Plugin named 'ManagerManager'. Please enter a unique name.
With TimyMCE settings
There is already a Plugin named 'TinyMCE Rich Text Editor'. Please enter a unique name.
It happened to me with ManagerManager, Timymce and any other plugins with an old version disabled.
You need to remove all old/disabled/duplicated plugins to make changes on the actual version.
Also happens with chunks if there is a chunk with the same name
