I can't access the Properties (?) panel after a while

[Qwertygiy]

It won't let me click or change SOME items, I can still change some properties, but not most, and puts something like this up:

at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpI(Unknown Source)
at java.awt.Container.dispatchEventImpI(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpI(Unknown Source)
at java.awt.Window.dispatchEventImpI(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

O.O That took forever to write down.
And I can still do stuff in the "Explorer" pane. (We need seperate names for those so that we don't have to use ROBLOX terms...)