Unusual slowness in Power BI Desktop Query Editor (expanding rows etc.)

Hi

I have data from Azure Document DB. When I edit the data in Query editor,  for example drill into a list, it may take me like 3-5 minutes to do this simple action. My computer specs are good, 16 gb ram, i7 processors etc. Everything else works fine on my computer. The "yellow balloons" just keep whirring and horizontally from left to right and nothing really happens..

Any idea what is wrong ??? Also, sometimes my queries hang in "Waiting for xxx-erp-document-db-azure.net" - message.

Thanks in advance.