Fix: When dragging a text in forward direction a selection is "dragged" by a double distance
Review Request #129758 - Created Jan. 3, 2017 and submitted
Drag and drop of selected text in forward direction sets wrong selection and cursor afterwards, see bug #374163.
This patch fixes this.
Added unit test (a bit ugly due to bugs in QTest: drag and drop blocks, so a singleShot timer as workaround is added).