Xcode 5 - Required plug-in not present in DVTPlugInCompatibilityUUIDs?
I modified a shell commands I found here to fix this for all my plugins.
To fix this issue:
XCODEUUID=`defaults read /Applications/Xcode.app/Contents/Info DVTPlugInCompatibilityUUID`for f in ~/Library/Application\ Support/Developer/Shared/Xcode/Plug-ins/*; do defaults write "$f/Contents/Info" DVTPlugInCompatibilityUUIDs -array-add $XCODEUUID; done