Ext aligning may be resetted depending on font

[MVV]

This works 100% on 1280x1024.

1. Delete wincmd.ini (or rename AFTER closing TC).
2. Start TC, set font Tahoma, bold, 10.
3. Maximize window.
4. Go to Tabstops configuration and enter positions 160, 230, 240, 320, 150 and don't touch other options.
5. Restart TC. Why extensions are not aligned with tabs now?

What is really strange: TC resets aligning only when first tabstop position is 160. If I set it to 159 or 161 at step 4, aligning is kept after TC restart.