Chart scaling is very glitchy

When I'm out've the house I use a macbook pro, thus I have to use the web version of Ctrader.
Now I don't mind using the web version, I think its half descent, but the chart scaling makes it unworkable.

Whenever I want to scale the chart (make candles bigger or smaller), it just flips out. 

Basically I can only have the chart fully zoomed in or out. Now I could use the zoom function in the left bar, but that's very counter intuitive.

Thanks in advance

Kafeldom