Cursor movement bug in math insets with split views

[aparsloe]

In a new document open a math inset and enter e=mc^2. Split the view 
into left and right views. In the right view ensure the cursor lies 
*outside* the math inset. Now in the left view try to put the cursor 
*with the mouse* between, say, "m" and "c". I find the cursor remains 
stuck at the start of the inset (before the "e"). It does respond to the 
arrow keys.  However, if in the right view I place the cursor *inside* 
the math inset, then on the left the cursor once more responds to the mouse.

The problem is present for me in both 2.1.0beta2 and 2.0.7 on Windows 7, 
but it has been there for a year or more, including on a Windows Vista 
computer (with a different mouse) and earlier members of the 2.0.x series.

Andrew