Expand when configuration honors the state of layout in design time and executes the when rule only during initial load. But once the layout is expanded manually or through server side when condition, it remains in expanded state for further AJAX requests. It is designed this way to always honor the user preference ahead of the expand when. There may be use cases where in the user expands the layout manually and expects the layout to remain expanded irrespective of whether the when condition is true / false. Also we have to keep in mind that this is expand when condition and not collapse when condition. 

How expand when works ?

Expand when is controlled by a hidden input field with name ExpandedSubSectionXXYY (where XX - section name and YY - layout id)

On Initial load,

* If expand when wins - layout will be expanded and hidden input field will be set to true

* If expand when fails - design time setting will be honored and input field will be set to blank

For conditions 1 & 3 -> Since the hidden input field is set to true, expand when condition will not be executed after initial load.

For Condition 2 & 4 -> If the user expands the layout manually, then hidden input field will be set to true and hence forth expand when condition will not be executed in server.

Possible Work Around:

Setting hidden input field parameter to,

• False -> will collapse the layout
• True -> will expand the layout
• Blank -> will execute the evaluate when rule