| Subject | English | Welsh |
| comp., MS | active document window | ffenestr dogfen weithredol (In an environment capable of displaying multiple on-screen windows, the window containing the document that will be affected by current cursor movements, commands, and text entry) |
| comp., MS | active window | ffenestr weithredol (The window in which a user is currently working or directing input. An active window is typically at the top of the Z order and is distinguished by the color of its title bar) |