You need to change the order of the section rules, and ends with:
element * MYLABEL
Starts with the only rule (element * MYLABEL) and check if you see anything.
Then add before that rule the selection rule of the parent folder (most likey the vob) which may not have that label:
element /vobs/MyVob /main/LATEST
element /vobs/MYVob/ParentFolder /main/LATEST
element * MYLABEL
That will only work if mylabel has been applied on all elements under a certain path.
Each parent folder above that 'MYLABEL' must be selected by the /main/LATEST rule.
If MYLABEL has been applied for all elements under A/B/C/D,
A needs to be selected by /main/LATEST
A/B needs to be selected by /main/LATEST
A/B/C needs to be selected by /main/LATEST
Then you end with element * MYLABEL.
If you only apply MYLABEL to a particular subfolder, and would like to be sure to see that label only on that subfolder, you can do:
element /MyVob /main/LATEST
element /MyVob/projects /main/LATEST
element /myVob/projects/subProject1/... MYLABEL
element * /main/LATEST
That way, any other subProjectX folder will be in /main/LATEST, except for the content of subProject1 (because of the /... three dots notation).