I set this feature at button F of ASSINABLE group. And it works as an On Off switch for this feature.
However, you can always turn it ON and note at the time of pressing Fill.
You only need to add Fill in the first beat of the bar, it will Fill 2/4.
Iff you press Fill from the 2nd beat onwards, it will Fill 4/4
https://www.youtube.com/watch?v=8yrZrlveyng
