casimero wrote:yes, this is what i want. the right term is "main menu" instead of "parent menu".
It is possible, although it's not really how X3 works. The main menu is "global" and will always be part of the page, unless you have entirely disabled the menu. Your options:
When you create a new page, go to the settings > page > advanced > page body classes, and add the no-header
class. This body class will effectively hide the entire header and main menu from the page.
Separate X3 website
Since you want to create temporary pages without the main menu, it sounds to me like you want to be able to create temporary galleries entirely independent from your main X3 website. If so, you could consider installing a separate X3 in a subfolder "clients" (or whatever). You could then disable the menu and design it only for your temporary galleries.
Optionally, you might consider our new Files app if you simply want to show a specific gallery to clients (etc).