Last CTRL+Z "loses" the caret in the Edtior

prpblem:

• open a segment with content, place the caret somewhere in the middle
• type "a"
• use "CTRL+Z
• two types of problems can be observed:
    - problem a: there is no cursor in the editor (fixed)
    - problem b: the cursor jumps to the front (not fixed; this is the correct for the very first snapshot: after opening the segment the cursor IS at the front => changed with "TRANSLATE-1356 Cursor is placed wrong after CTRL+Z")