Double-click doesn't "fill" screen I have a 2017 MBP connected to a monitor with HDMI. On my laptop screen, when I double click the top bar of a window, it fills the whole screen up to the Dock. However, when I do that with a window that's in the monitor's screen, the window fills the screen vertically but not horizontally. Meaning I have to still manually resize the window.

Is this by design or am I doing something wrong?
Only double click show you all content.  Press shift + double click fill all display :)