When using the Preview update Team Development Contextual Menu (X Evolution 3) on a list of objects, a Preview is triggered to get the list of selected objects from the GXserver repository:
========== Receive changes started ==========
Contacting GeneXus Server at 'http://....'... done!
Exporting Data Selector 'SampleObject'...
GeneXus Server: Partial update requested by GXTechnical\genexus
GeneXus Server: Processing file...
GeneXus Server: Checking Import References...... Finished
GeneXus Server: Reading import file objects...... Finished
GeneXus Server: Exporting Data Selector 'SampleObject'...
Processing file 'C:\Users\genexus\AppData\Local\Temp\tmp576D.tmp'...
Checking Import References...Finished
Reading import file objects...Finished
Receive changes Success
========== Preview Update started ==========
Preview Update Success
Then, the Team Development update dialog will be instantiated with the selected object list from the GXserver repository; the user can actually execute the update operation or cancel it.