If you move some selected track or section of tracks and want to join them to another part of the layout, it is possible more than one joining place to occur.

See the example on the picture below.

The join will occur on the place, where there are red and green arrows. But if you want to make the join on the other possible connection (yellow arrows), just press the Tab key.

See also
How to move the tracks
How to disconnect and connect the tracks