Each change of variable values results in a direct recalculation of the geometry in the 3D view. Depending on part size this may last a moment. If you want to change several values, possibly you can work faster when stopping the recalculation via Recalculate 3D geometry on/off temporarily.
Functions in the Seamless mode are mostly according to the ones in PARTdataManager. A detailed description of all functions of 3D view can be found under Section 3.1.7.6, “ Docking window "3D view" ”.
Detailed information on the context menu commands can be found under Section 3.1.19.6.2, “ Context menu commands Part view ”.