Mouse Scroll WITHIN A Data Validation List & Option Macro Assistance

I'm trying to do a few things actually. I am somewhat a newb at programming, although I do understand how C++ and the coding works within Excel. To me, it's like the English language...knowing all of the vocabulary and formatting it right is important. If I don't know the vocabulary, I don't know what options I have.

This tool is being used in the call center I work in. It is to help eliminate repititious information used to notate accounts. I have attached a picture of what the tool looks like so you can have a better idea of what I'm working with. Here are a list of things I'm trying to do which I have searched and not found answers to:

1. I am trying to use a middle mouse scroll to scroll through validation list. This list information is located on a different locked tab. Basically, I have a few rows where a drop down selection can be made and it would be easier to scroll rather than manually moving the slider within the validation list.

2. As you can see, this "tool" an employee and I have created has many buttons. What I would like to do is to be able to click a button on the right and have it "stack" text within a single cell. In other words, if I click the button once, the text may be entered into the "actions taken" cell. If I click another button, I can have the option (or maybe a little "+" next to the button) to add this button's information to the end of the information already entered within the "actions taken" box. I've tried recording and using the keyboard and selecting "end" and then having the text added, but it didn't work. I've seen "loop" VBA code, but I don't want something to repeat, I want it to stack in the cell when clicked manually.

I'm sure there is a way to make the tool much better using VBA code and not use Excel, but I don't have an extensive knowledge of Excel to do something like that. I'm a very fast learner and understand how the coding works, so if you have an idea which may help, and you understand what I'm trying to do here, please provide your .02.

Basically, it's used so the Customer's name and phone number are entered manually, and then just about everything else is automated by the use of the buttons on the right. If I could get the 2 above options to work, it'd be perfect. I just figured out I could eliminate screen flicker and hide the macros working by using: