Try hide subpanel:
edit suitecrm/modules/Project/metadata/subpaneldefs.php: remove in $modules_exempt_from_availability_check ‘Holidays’=>‘Holidays’
But Holidays show in module!
I have logged a bug on the SuiteCRM GitHub Repository, as sub-panels should be configurable in Admin -> Display Modules and Subpanels.
Thanks for highlighting this.
Admin -> Display Modules and Subpanels. Hide subpanel in all modules. I try hide only in Projects module