offline chart disappearing PLZ help

 

so I added a custom timeframe which is 90M timeframe, I used 30M chart and added the "period converter" script multiplied by 3.

I added my EA and unchecked the offline checkmark on the properties of the chart so that my EA works.

But every time a re-start my mt4, the offline 90M chart goes back to 1H Timeframe.

How can I make it so that it keeps the 90M chart after restarting.



Plz help 

Reason: