Add scroll bar to Compute Column feature

[hanneoberman]

• Enhancement: scroll bar next to variables to select for computing new columns.
• Purpose: give visual feedback for scrolling through the variables in the data.
• Use-case: the undergrads I teach had trouble recognizing where to select existing variables to create a new var.

Is your feature request related to a problem? Please describe.
Not a problem, just usability.

Describe the solution you'd like
Add a scroll bar to the Compute Column feature: when using the option to select (pointing finger, not R) to create a new variable, the existing variables are presented at the top left of the screen. I'd like it of this list of variables was easier recognizable as a scrollable list. A scroll bar next to the list would give users visual feedback to scroll through the available variables.

Describe alternatives you've considered
Not applicable.

Additional context
With list I mean the 'Moon', 'Other' and 'diff' variables.

[JorisGoosen]

I've added some scrollbars

[hanneoberman]

Nice! Thanks :)

[JorisGoosen]

You're welcome and it does look better ^^