I installed an extension called Layer Manager a while ago. I tried to remove it by unticking the box under Preferences. I had a message that it could not be removed dynamically but would not load next time I fired up SU. However, the item still remains in the list, albeit with the box unticked. Does it ever disappear entirely?
Unchecking and checking is only a load control.
Did you install it using a extension manager, like Extension Warehouse ? or the SketchUcation Plugin Store ?
If so, you may be able to uninstall it via those interfaces.
If not, you can manually delete the “jbb_layers_panel” directory, and the “jbb_layers_panel.rb” file from the user “Plugins” directory.
Then the next time you start SketchUp the extension will not even appear in the control listing.