rearrangeBlocksInMultipleTracks(dictOfTrackIdsWithListOfBlockIds)#handles undo and callbacks for redrawing
callbacks._setCursor()#cursor is still on the same item. But the item might be further to the right now when additional block boundaries have been introduced to the left through contentLinks
right()# continue typing on the right side. This was added in 2020 to create a "split is an item" feeling
defjoinBlockWithNext(blockId):
"""written for the GUI which can join blocks with the mouse"""