I’ve noticed this for some time now!
In Grasshopper on macOS, you can’t use the system-wide shortcut CMD+A to select everything in most component text input fields, except in Panels.
This is most frustrating for example for components like Expression, where there is a substantial predefined text, and you can’t quickly select and delete it.
Instead, you need to move the mouse, drag a selection or double-click, and hit delete.
The editor also doesn’t open with the text pre-selected, which could be a potential workaround, since you’d only have to hit delete in that case.
I’ve also noticed that when you attempt to use CMD+A to select the entire, set attribute in a Set … dialogue from a component input right-click menu, everything on the canvas gets selected, instead of the set text (e.g. 120), and the dialogue instantly closes, which is also not ideal.