Hello Ali
When you have a workspace with different connections, AOLAP only knows about each query at the point when the Sheet is selected. This is a performance optimisation... so, for example, if you have a worksheet with 3 different connections then instead of AOLAP opening all three connections on load, it will only open the connections used on the first page.
When you open a Sheet which uses a connection with prompts, the Prompt Dialog will appear and you enter the required values.
If you open a second Sheet with a different connection but with Prompt Merging enabled, the Prompt Dialog will still appear but the prompts which are the same as used in the previous query will be prepopulated with the values previously entered.
In your scenario this means that a fully populated prompt dialog will appear so you should just need to click "OK".
At this time there is not an option to not display the prompt dialog is all variables are prepopulated.
Hopefully this explains the current behaviour.
Kind Regards
