Control whether Windows command line commands run in new window

In my Windows command prompt, sometimes when I run a command it gets executed in a new command prompt instead of the current one. Is there a way to control this (force commands to always run in current window or always in a new prompt)?

Example: running ipython.exe opens the interpreter in a new prompt (and i've seen this behavior with few other commands which I can't recall right now).

There are basically two types of Windows applications, console based and window based. This is set by the developer before compiling the code. CMD.EXE is console based, NOTEPAD.EXE is window based. If a console based app is launched from cmd.exe, it will always open in the same window unless you do something to change that (like use the START command). If an app opens in a new window, then it is either window based or the program itself was coded to create a new window.

If the program itself opens a new console window, there is nothing you can do to stop it.