Adding a tie will select a note in another voice in preference to same voice

Ubuntu 14.04, GIT commit: 83622b0

1) voice 1: enter two half notes E C
2) voice 2: enter whole note C (same octave as the C in voice 1)
3) press "5 +"

Result: the whole note C in voice 2 ties to the half note C in voice 1, even though a quarter note is added to the next measure

Same result if you add the quarter note C manually then leave note entry mode and try to add the tie.

Before:

After:

It's great that it's *possible* to tie across voices, but adding a tie (whether in note entry mode or not) should not accept a note that is early than the endpoint of the first note.