I have built a textbox dropdown AngularJS component which works great in Chrome, Firefox, Safari and Internet Explorer.
A feature of this component is that you type in a string, and then can use the up/down arrow keys to scroll through suggestions.
In Microsoft Edge, as soon as you hit the down arrow, the following text is added to the input box:
briefly explain your changes (corrected spelling, fixed grammar, improved formatting)
<input type="text" />
If I understand correctly, you are having an issue with the autocomplete feature. Simple add "autocomplete='off'" to your input and that should disable the feature.
<input type="text" autocomplete="off"/>