User Problem

If I have included an array column, such as the "Labels" column, that you've chosen to use the 'Explode' grouping with and a work item doesn't have a Label then the query will only return work items with labels. The 'Explode' grouping for an array column uses the explode() function which will ignore any null rows for the array column. If the explode_outer() function was used instead the null rows, aka work items without labels, would also be included in the query's results. 

Suggested Solutions

Update the array functions to use explode_outer() instead of explode(), or add a new option of explode_outer() in Visual mode queries. 

Current Workarounds

Use the explode_outer() function in a SQL mode query or use one of the other array options ('Group', 'Concatenate', etc.) in your Visual mode query.