Hi Jay – first of all, sincere thanks for picking up a copy – I really appreciate the support.
It’s pretty rudimentary at the moment and you may only be referring to the dedicated alpha channels, but you can already start both videos in slots A+B simultaneously (thereby syncing them assuming the same source length, play-back speed and that you don’t manually jump to a new point in either video). It’s not particularly obvious, but there’s a small yellow icon in the video A section which will trigger/restart both simultaneously. I often use this in a similar way to the one that you describe (different effects over the same source). You can also use slot A as an alpha channel by selecting the “alpha_blend” mode (in which case B becomes the background), which may provide a partial way of doing what you want with synced alpha content in some circumstances.
It doesn’t trigger videos in the dedicated alpha slots at present though (I tend to use that for simple image overlays or animated gifs), but that shouldn’t be difficult to add. I agree that a more sophisticated set of options in this regard would be great, including a “global” start frame setting. It’s a great suggestion, so I’ll have a think about the best way of achieving it and work towards including it in a future update.