"Compose" box is not made smaller when screen size changes

I work with a biiiig monitor with Full HD resolution. I enlarged the “Compose” box (Create a new topic, reply to a topic - where I am just typing this) quite a bit. Now I am off for today and back to the 15’’ laptop display with smaller resolution and the box is partly hidden behind the header and I couldn’t find a way to make it smaller and usable again.

Edit: Ctrl + - worked to see that pulling thing again and I could resize the box.


Another workaround: Reloading the page resets the composer to its default size.