Old Window border style on Delphi MDI child form

[Clayton A. Alves 0]

In Delphi 7 (don't ask) the MDI form (window) is displayed using Windows 10 style. But the MDI child is using the old Windows style.

Does anyone has any clues on why this happens ?

 

I've attached a screenshot of this problem.

 

Delphi Version: 7
Windows Version: 10

Edited 4 hours ago by Clayton A. Alves

[Uwe Raabe 2021]

Windows 10 doesn't support MDI child forms with Windows 10 style. Microsoft deprecated MDI since about XP and proper support for newer features will probably never be done for MDI windows.

 

See also: MDI window title in Windows 10

 

 

[Anders Melander 1748]

6 minutes ago, Uwe Raabe said:

Microsoft deprecated MDI since about XP

Any authoritative sources for this?

I've seen people make the same claim many times about both COM (claimed to be superseded by .NET) and GDI (claimed to be superseded by GDI+). Both ridiculous claims.

 

Just because MDI windows doesn't support the same features as SDI windows doesn't mean that they're deprecated. The documentation certainly doesn't give any indication that it is so: https://learn.microsoft.com/en-us/windows/win32/winmsg/multiple-document-interface

[Remy Lebeau 1349]

1 hour ago, Clayton A. Alves said:

In Delphi 7 (don't ask) the MDI form (window) is displayed using Windows 10 style. But the MDI child is using the old Windows style.

Does anyone has any clues on why this happens ?

It is a underlying Windows issue.  Microsoft simply doesn't render MDI windows using modern styles or high DPI support (ie, MDI does not operate under DWM).  That is why Embarcadero finally decided to revamp their MDI system in the VCL in Delphi 12:

https://docwiki.embarcadero.com/RADStudio/Athens/en/What's_New#MDI_Reworked_for_HighDPI_and_Styles

26 minutes ago, Anders Melander said:

Any authoritative sources for this?

Not on-hand, but I've seen MS employees verify the issue.  I also found this tidbit, take it with a grain of salt:

https://www.akadia.com/services/dotnet_software_design.html#The MDI (Multiple Document Interface) Approach

Quote

MDI was used a lot with versions of Windows prior to Windows 95. However, Microsoft researchers discovered that users found this split artificial and confusing. So from Windows 95, Microsoft announced that MDI would be deprecated and it should not be used for Windows applications ... well, Microsoft's story on MDI has never been consistent; legacy support has continued to be included with windows and the .NET Framework supports the MDI Approach in an excellent manner.

26 minutes ago, Anders Melander said:

I've seen people make the same claim many times about both COM (claimed to be superseded by .NET) and GDI (claimed to be superseded by GDI+). Both ridiculous claims.

Nobody ever claimed that .NET would replace COM.  GDI+ augments GDI, but does not replace GDI.

Quote

Just because MDI windows doesn't support the same features as SDI windows doesn't mean that they're deprecated.

It is a well-known fact that after XP, MDI has been left behind in visual handling.  MS simply never bothered to update MDI for modern systems.  Feels like deprecation to me.

 

Edited 2 hours ago by Remy Lebeau