Good one, I was just strugling with this myself with translatable objects. The most ideal sollution would be that in the override page title we could use objects to generate the title. Nice one for the feature request post. For now I solved it to leave the title empty and use a textbox and a class to show the translation. Not ideal.
If you only want to change the tabtitle in the browser you can use this widget: https://appstore.home.mendix.com/link/app/2810/First-Consulting/Dynamic-HTML-Title. But that is not a sollution for form titles.
If someone found another sollution to dynamicly change the form titles.....
In addition to Ronald suggestion, I don't know a solution to update the page title. But an easier way to create your own title:
If you use the component called 'Label', at least in Mx6 (and I think 5.19+) it has the option to use parameters (identical to how you setup feedback or popups in microflow).
Using the label, if you set it to render mode: "Heading 1" and add the class: mx-title you will get a label that looks 100% identical to what a page title looks like. This is the same solution as suggested by Ronald, however it saves you the time of having to style a textbox.
The only problem with this solution is that it doesn't change the title you see in the browser header. That is something you currently cannot change
It am struggling with the same problem. I think it is very common to select an entry in a List form and then open a Details form to show all info for that entry.
The Details form should refer to the entry the list (which most probably is a descriptive name). Yes, you can use a Text widget for that, but why not the page title? That saves valuable space in the Details form.
I came pretty far by using a Microflow that opens the Detail page from the List page. See: https://docs.mendix.com/refguide/show-page
Add: Parameter; specify the Entity which is used in both List and Details form
Add: Action activity = ShowPage; specify next parameters:
The result is that the page is openend with has the title "$currentObject/<Attribute>". Not exactly what I had in mind!
I challenge the MX dev team to add support for Parameters/Attributes in the Show Page action.