Lead Sheet for transposing instrument frustration.

So, if anyone can help me that would be a godsend.

If I create a score for alto sax and ad chords to it, the notes of the alto will play correctly transposed (a written "C" note will sound like an "A" note a major six up). YAY

BUT the chord on the lead sheet will not be transposed, resulting in some infuriating bi tonality if I leave the score transposed.

If there is a "E" on the melody and an A minor on the chords, it will sound like a C# note over a A minor chord, and not a C# note over a F#m chord.

Can someone find a solution to this?

Is there a box to tick "transpose chords with melody"?

I need the chords to transpose with the rest of the score.

I'm lost.