Bars fill line problem

I have a 4 bar per line, 32 bar lead sheet. I deleted 20 of the bars to leave 12 bars (4 bars x3 lines) but the last four are truncated and dont fill the line. I have Layout options set to limit 4 bars per line and no matter how I do the system break in Engrave but it wont let me do it. Ive added a bar and tried system break, still breaks at 3 bars. What am I missing? This seems overly complicated for such a pedestrian task. Thanks for you help

In Layout Options > Note Spacing, set this option to something smaller in order to get that last system to fill the width of the frame.

Ah thank you, that did it. Wow, in Guitar Pro I just hit ctrl return. Thank you!