While scanning, it is desirable (at least until complete CREST integration is completed) not to make the IGB window very large, for example so you can update signatures while moving your probes. However since the 1.8 update there are some issues I've noticed with a "small" browser window.
When the width of the browser window becomes less than 751 pixels wide, the base menu becomes a vertical row. (751 pixels wide | 750 pixels wide)
While scanning, it is desirable (at least until complete CREST integration is completed) not to make the IGB window very large, for example so you can update signatures while moving your probes. However since the 1.8 update there are some issues I've noticed with a "small" browser window.
Reference: base.css