This issue is far from solved for me. Videopad is being a bit of a bitch. And I rebuild most of the sequence to get the result I wanted 🙁
A work around that does seem to work; Grouping together the items (a+v) to the right of the picture I want to extend. Then I am able to move that group to the right making the rest of the items in the sequence also move a bit, and creating space for me to extent the picture on the left of the grouped items. It's a bit of extra work but it gets me the result I want. Note: turns out grouping things together is not needed, just selecting them before moving seems to be enough.