References to not open documents are not kept in memory after evaluation

[fredrikhr]

If a region references a region in another file that is not currently open, a normal @ref reference is evaluated as if it were a @forceRef. Multiple repeated executions of the region trigger the @ref evaluation each time. However, if I open the file in which the referenced region is located, the first evaluation is stored in memory, and subsequent calls use the stored value instead of re-evaluating.

It should not matter whether a file is opened or not. A reference should only be evaluated on first call, subsequent calls should use the stored value.

[AnWeber]

I have reverted the changes to the ImportMetaDataHandler from v5.2.0 and it also saves unopened files as before. With v5.2.1 it works again.