Need help ASAP - Insert column greyed out

[sumdumgai]

Have been doing query design changes for a long time and all of a sudden, after I add a table to my query, the 'Insert Columns' icon is greyed out. "Insert Rows' is showing but not "Insert Columns'. Any help would be appreciated. Running Office 365 (Office 2013).

 

[sumdumgai]

More info. I found that if you right click on the bottom half (showing the fields) of the query design window, then the 'Insert Columns' icon will activate. Is this normal?