Method JSPTextEditor.handleCursorPositionChanged resets text selection on each change in cursor position, except when selection has non-zero length. That is done to inform vpeController know of that change. However, setting selection is quite a time-consuming operation, it makes navigating with cursor about 20% slower than in HTML editor. Previously to changes done for JBIDE-7059, handleCursorPositionChanged directly invoked method vpeController.selectionChanged. Commits to JBIDE-7059 do not explain why that was replaced by resetting selection.
I suggest restoring the previous method implementation.