Hello m_aalaei,
The first solution is to create another layer to put it on it.
3D view
You can select all your project except the morph you do not want and do a right clic to select the option : "Show selection in 3D"
2D view
You can create a pen set or a graphics override to mask your morph by a white apparence on a white background. You can find these function by the menu "Documentation".
Either you can change the morph 2D parameters by modify these options :
By this last way you are able to mask a element which is above your cutting plane.
Christophe - FRANCEArchicad Designer and Teacher
Archicad 15 to 27 FRA FULL
OS 11.6 Big Sur - MacBook Pro 2017 - 16Go RAM
"Quality is never an accident ; it's always the result of an intelligent effort" John Ruskin