Evaluate if a Section layout is collapsed or expanded

Section layout collapsibility occurs on the browser and does not send any information back to the server. To achieve what you want, I recommend using a!richTextDisplayField to show a section label with a side arrow. Use a dynamic link on the arrow to change the icon and call other saves. You can use a local variable to store whether a section is collapsed or expanded.

My feature request would be to parameterize this within a!sectionLayout() - i.e. a parameter akin to "isCurrentlyCollapsed" (optional) which can be associated with a local variable to either control things externally elsewhere on the form, and (preferably if possible) also allow the collapsed state to be controlled from externally as well. 

I vaguely understand what you mean that it's handled by the browser, but is it completely unfeasible that the component could be expanded such that there's an event thrown when the collapse expando is clicked/etc?  I've had many situations in the past where this would be desired behavior and of course our hands are bound, unless by use of a homebrew "fake" section layout component, which works but is clunky and seems like it *should* be unnecessary.

I would love to see this new feature to load data in a section only if it is expanded. At the moment I have to do what Danny suggested

I would love to see this new feature to load data in a section only if it is expanded. At the moment I have to do what Danny suggested