I'm also running Aero Glass on Win 8.1.
Ribbon-enabled windows, such as Explorer and WordPad, use an entirely different method to paint the title bar, and thus are not handled by the normal DWMGlass.dll.
Big Muscle released some additional components that work with Aero Glass and allow you to resurrect the glow, but there are some downsides. This is from my all too frail memory, but I believe UxThemeSignatureBypass64.dll and UxThemeSignatureBypass32.dll circa March 8, 2015, invoked via the AppInit_DLLs key will color the titles of ribbon-enabled windows. Here's what I see (note that my text is set to be white and the "glow" backing in my theme atlas is actually dark):
As you can see in the Beyond Compare Options dialog at the upper-right, it essentially causes any text that uses the same API calls the ribbon-enabled windows use to be painted with the "glow" backing. It's a minor inconvenience I can live with to have the more integrated title bars.
It's been a long time since I set this up, but I see I left myself an "InstallSignatureBypass.reg" file... This is what's in it:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows]
"AppInit_DLLs"="C:\\AeroGlass\\UxThemeSignatureBypass64.dll"
"LoadAppInit_DLLs"=dword:00000001
"RequireSignedAppInit_DLLs"=dword:00000000
[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows NT\CurrentVersion\Windows]
"AppInit_DLLs"="C:\\AeroGlass\\UxThemeSignatureBypass32.dll"
"LoadAppInit_DLLs"=dword:00000001
"RequireSignedAppInit_DLLs"=dword:00000000
Note also that I stayed with Aero Glass 1.4.5, not the latest, as I saw some visual glitches with 1.4.6.
The above is 100% stable for me. I get long uptimes between Windows updates that mandate reboots.
-Noel