Hi Kamel
When you create a new layout, you can assign it to one of the open projects. Later you can open this layout only if this project is open.
Always the layout (and the project) you used when you closed P6 will be opened after start of P6.
After you changed to a different project the layout will remain.
Regards
Dieter
Hi Dieter ,thank you for the
Hi Dieter ,thank you for the confirmation , there is no way to ovoid reopening the appropriate layout.  
Hi Kamel When you create a
Hi Kamel
When you create a new layout, you can assign it to one of the open projects. Later you can open this layout only if this project is open.
Always the layout (and the project) you used when you closed P6 will be opened after start of P6.
After you changed to a different project the layout will remain.
Regards
Dieter