Tested with L2R rows and mouse highlight on a single line.

Tested with L2R rows and mouse highlight on a single line.

 xdisp.c (mouse_face_from_string_pos): Initialize the `found'
 flag to zero, and exit the outer loop when it's non-zero.  Bail
 our early if no row in the window belongs to the highlighted
 string.  Always back up after exiting the second loop.