In the days before heavy security it was quite possible for programs to monkey around with other programs' UI in all sorts of way. A lot of that is still possible from an administrator or SYSTEM-privileged context. Some 15 years ago I wrote an Internet Explorer addon that added stuff to the statusbar by hooking into the IE window's message pump and intercepting winforms calls. Shit was wild.
Growing up in the 90s, I remember an article in Visual Basic Programmer's Journal teaching subclassing in VB by hooking into Notepad and adding a font picker (via a new menu entry that opens the font dialog) to change the text control's typeface. (This was long before MS added that same feature)
Growing up in the 90s, I remember an article in Visual Basic Programmer's Journal teaching subclassing in VB by hooking into Notepad and adding a font picker (via a new menu entry that opens the font dialog) to change the text control's typeface. (This was long before MS added that same feature)