Better selection in CAS expressions

[marcin1812]

Hi, is there any method (apart copy/paste) for more accurate selection within expression in CAS?
Currently I Can mark whole expression in stack by using cursor Up and Down.
But I want to mark part of expression. and I Cant.
Copy / paste is quite slow and clumsy...
I thougth that cursor left/right should divide selection by for example parts of expression.
But I didn't find any key combination to do this.

Is marking really so unfinished function after more than 10 years of development firmware?

Rerards