Please share pointers/links over customizing Page Properties for Classic UI in aem 6.5.5.
I need to create a new tab with fields. Touch UI - I know already.
Unlike the Touch UI, Class UI dialog does not support resource merge. Once you create a classic dialog, it will override the parent(sling:resourceSuperType) dialog completely. You can do two things.
Check /libs/foundation/components/page/dialog/items/tabs/items/basic for how to include tab in classic ui.