If price on the chart is not filling vertical axis / space as below, change the chart settings, see below.
Un-check Fit Studies from the Price Axis menu drop-down at the top of the vertical price axis to the right of the chart.
Right-click on the right side vertical price axis. Choose Scale Price Chart Only.
How to scale an indicator in TOS:
If you are noticing that the charts on your screen in TOS are squished, scrunched or tiny and hard to read, chances are you will need to make one quick adjustment to fix this visibility issue.
Most of the time this will affect your Voodoo Lines, Lay Up Indicators, or any indicator that displays significantly above or below the area for price.
Please be sure your indicator is applied to the chart so you will be able to note the difference once the changes have been made.
Next, on the top menu in Thinkorswim, select Style > Settings > Price Axis
This will bring you to the menu where you can set the scale setting.
From here you will need to make sure and set the "Scale:" to Auto, then
UNCHECK the box for fit studies.
Click "OK" and you should be all set.
TOS - How do I change the colors of my indicator?
Voodoo Lines - Settings
Trading View - Username