Fix calls to OnCaretMove()

Based on TortoiseSVN revision #25710.

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Ensure drawing of whitespace indicators is always right of the margin

Based on TortoiseSVN revision #25712.

Signed-off-by: Sven Strickroth <email@cs-ware.de>