It appears to me that in KM10, in a Custom HTML Prompt, calling window.KeyboardMaestro.ResizeWindow(x,y,width,height) doesn't do anything. (x,y,width,height are variables). Can anyone verify this? I want to make sure I'm not going crazy[ier]. Edited to add @peternlewis to this.

I using window.KeyboardMaestro.ResizeWindow() extensively, I too can confirm that it is working in KM10 (note: I using Catalina)