Win10-64 bit: it don't change the custom video mode

Hi, from many days I was exporting videos only in 1080x1920 or 1920x1080 and then today changing by hand these numbers to 1280x720 it was never changing even if trying more of 7 times. At the end Shotcut was applying my changes only using the HD 720p 25fps. Now it is all right.
thanks for the patience.

Are you adding your custom export setting to your Custom presets first?

No, in my presets I have only “Portrait full HD”, because missing in the Video Modes list. and I am using the HD 720p 25fps choosed from the list named Non-Broadcast.