In Strategy Web 10.6, it is possible to hide the visualizations gallery for Visual Insight using the following parameter in URL API:
hiddensections=gallery
http://ServerName/MicroStrategy/asp/Main.aspx?evt=3140&src=Main.aspx.3140&documentID=D0DB0DE9456554711034F1ABB5B248FB&hiddensections=gallery

Using the above URL, the visualizations gallery will no longer be seen:

Once the visualization gallery is no longer seen, if needed, it can be added using the View toolbar and selecting the Visualization gallery again:
