As discovered in D524 it is important to set the data storage BEFORE the auto selection mode has been enabled. This is required since calling SetAutoSelectNewNodes directly performs a check to find matching nodes. If the data storage was not set before, no nodes will be found. This is only relevant when the plugin is initially opened and the node selection widget is setup. However, if a data storage will be reset, no new check for matching nodes will be performed.
To not rely on the order of the function-calls, (re)setting the data storage of a node selection widget should use DetermineAutoSelectNode or similar to find matching nodes if auto mode is enabled.