The traversal of the slides as the pdf is prepared seems to be defined in "TeXmacs/progs/dynamic/fold-edit.scm", more precisely in the "process-screen" function which calls "dynamic-traverse-buffer".

I don't fully understand the code behind "dynamic-traverse-buffer", but I see that it checks for the presence of a "keep-folded" tag. This tag does not seem to be defined (I can't enter it as \keep-folded into a TeXmacs document).

On the other hand, a \keep-unfolded tag does exist and can be entered via the menu as Insert->Fold->Traversal->Keep Unfolded. Intuitively, I would expect this tag to keep its content folded, but it is not checked for in the "dynamic-traverse" function. If this is the intended function of "keep-unfolded", then this would be a good workaround for this bug, you could put executable folds into a "keep-unfolded" tag.

I was wondering if anyone could comment on the purpose of the "keep-unfolded", "keep-folded" and "fold-back" tags.

Most graphics included using Fold -> Executable don't get exported to pdf. They only show as a box with the text "Busy...". From the plugins I've tested only Graphviz produces some output.

Grpahics in sessions do produce output in the pdf.

Note also that the figure counters get incremented on every pdf page.