Unfortunately no progress on this yet, but I might have a work around for you. On my system if I run the following IDE macro:
Sub OpenFindInFilesFromVABar()
DTE.ExecuteCommand("Edit.SelectionCancel")
DTE.ExecuteCommand("Edit.FindinFiles")
End Sub
the Find in Files dialog is opened, even when focus is in the VA context field.
If this works for you, you can bind a keyboard shortcut to this IDE macro in the IDE options dialog.