The Bug:

The grey word that is currently selected in the autocomplete dropdown can overflow the text box in command blocks if it starts far enough to the right.

Steps to Reproduce:

• Place down a command block and open it.
• Paste the following characters inside of it.

• execute run execute run execute run execute run 

• Look at the command suggestions displayed.
• Take note as to whether or not command suggestions in command blocks can appear outside of the text box.

Observed Behavior:

Command suggestions in command blocks can appear outside of the text box.

Expected Behavior:

Command suggestions in command blocks would not be able to appear outside of the text box.