I'm trying to create a shortcut to an Ant build target:

1) "File" -> "New" -> "Ant Build Scripts" -> "ShortCut to 
Target"
2) Check only "Add a keyboard shortcut" in the next screen
3) Specify the target of an Ant build.xml file
4) In the next screen specify a shortcut key combination 
(e.g. Ctrl-B) and remember it
5) Finish the "New Wizard - Shortcut to Target" dialog
6) "Tools" -> "Keyboard Shortcuts"
7) Click on the "Shortcuts" button at the top
8) Find your shortcut key, select it, click the "Remove" 
button, then the "Close" button
9) Repeat steps 1, 2 and 3 above
10) Enter the same shortcut (the one previously entered in 
step 4 and removed in step 8)
11) Notice that the "Finish" button is dimmed for this 
shortcut (but not for others, e.g. Ctrl-O).

I suspect this item is related to issue 34800.