Multicursor: Pressing Backspace over whitespace gives different results

Observation: It seems that logic was introduced to delete multiple whitespaces at once, not one after another like in former versions. That may be related to this bug.

• Have multiple cursors after leading whitespace (e.g. the typical indentation within blocks), in the same column
• Press backspace
• Expection: One space or all spaces are deleted, cursors are still in the same line and at the same column
• Result: All whitespace is deleted (ok), the first cursor is still the correct line and first column, but the second cursor is in the previous line and the line containing the spaces is removed

See attached video for a demo.