Main elements underlie certain restrictions with respect to where they can be moved along the timeline. This is so because the software wants to prevent a user from manipulating parts of the show which are not completely visible, inadvertently creating gaps between elements. Normally sub elements (transition and overlaid elements), on the other hand, can be moved around freely within their respective tracks in the timeline because they do not have the potential to create invisible gaps.
If you want to do so, you need to load additional elements before and after first and last elements.
The movement of a main element however is restricted so that it cannot begin later than the last main element that is currently loaded in OTM. To avoid problems you are not allowed to change first and last loaded elements to sub or main elements. This is why the main/sub element buttons are disabled for these elements.
Also sub elements are restricted; if the sub element is the last loaded element, you cannot convert it to a main element. As shown in the below screenshot, the sub element on the last track cannot be converted to a main one as it must not start later than the last main element located on track five. As an overlaid element it is related to Music 2 and may start later.
There are two ways to work around this restriction:
- Load more elements into OTM so that the formerly limiting element is no longer the last loaded element
- Use the "main/sub" button to convert the main element which you want to move into a sub element which you can now move up to the current end of the time line.
If you use the second method, you will find that you cannot convert the moved element back into a main element unless you also load the next transition.