This bug is the most annoying bug I have found yet. It kept messing up my responsive layout and I just couldn't figure it out. Has taken me all day to work it out.
When Upfront generates a grid for reponsive text if the text on the main 1080 display is dragged out wide it will break all the responsive layouts, even if the text has been resized on that layout.
The weird thing is that it only happens when the text is to the right of an object. It can be any object it seems, even another text element.
The weird thing is that when the text is to the left and on main 1080 display is has been dragged out to be wide then it doesn't break it.
Here is a video showing the issue.
This is a very glitchy bug and if you re-position things a few times you can probably get it working OK but when you have 4 or 5 components in a region this bug becomes really promounced and will cause major issues if you ever try to have more than one object on a row.
I notice that the themes you build yourself only have one item or group per row so I suspect you may know about this bug but maybe this gives you some more insight. The annoying thing is that even if you hide the element in the responsive view, Upfront will treat the other objects as if it is still there and push them all over the place.
I have lost another day to a random Upfront bug that has probably already been reported several times but I have no way of knowing as you don't have a bug tracker or anyway of letting people know what the issues are. I really like upfront but the commitment in time has been unreal and there are no bug fixes being released. I've been tracking some simple issues with large impact for 3 months and no fix released (like the JQuery-UI issue with the code window).