This bug was originally marked as duplicate of bug 207810, that is already resolved. This bug is still valid, so this seems to be another bug, but it might be related.
Build: NetBeans IDE 7.3 Beta 2 (Build 201211062253)
VM: Java HotSpot(TM) 64-Bit Server VM, 23.5-b02, Java(TM) SE Runtime Environment, 1.7.0_09-b05
OS: Windows 7
Maximum slowness yet reported was 3960 ms, average is 3960
Created attachment 131210 [details]
DiffSidebar.initialize() is adding a file listener in EDT.
Reassigning. Please evaluate.
although it appears to be a stuck native window file system it's true we should not access FS in EDT.
Integrated into 'main-silver', will be available in build *201307262300* on http://bits.netbeans.org/dev/nightly/ (upload may still be in progress)
User: Ondrej Vrabec <firstname.lastname@example.org>
Log: #225955 - org.netbeans.modules.masterfs.watcher.Watcher$Ext.register: LowPerformance took 3960 ms.
do not attach or detach filechange listeners in EDT
*** Bug 227805 has been marked as a duplicate of this bug. ***