Zoom and Scale- One thing I discovered today when setting up my charts on this topic. Scaling is also affected by your moving averages and price marker settings. When you configure your Levels setting like Y Low & Y High or Pre Mkt Low & High or Moving averages indicators in the study config section when right clicking on chart, you may want to un-click the "include in scale" box in the config ex which will allow you to Zoom/scroll into you area of interest without making the candlesticks or chart smaller.
Study Config--> highlight study--> hit configex--> check or uncheck the "include in scale" box
I left it checked for Candlesticks but removed it for everything else and I have beautiful zoom in & out scaling.