To Apply a Clip Mask by Polygon

Select the Clip Mask view control.
In the tool settings, click the Apply Clip Mask By Polygon icon.
Enter data points to define vertices of the polygon.
When all vertices are defined, click the Close Element button to close the polygon.
If only one view is open, then the clip mask is applied.
If more than one view is open, enter a data point in the view to which clipping is required.

Applying a Clip Mask by Polygon