Thanks MarkOz, reload of FSX now has brought up a drop down list properly of the tanks with a slider control - seems to be a windows issue (the way windows draws windows not WIN generally). Not sure but I have the Bojote tweak cfg file and an external frame limiter and while FSX runs very well like this it does seem to be creating some conflicts when you change screens (aka window display) I have also noted that REX weather wants to take over the whole process until it is completely loaded up and this does appear to cause some conflicts.

Not sure about the engine start issue as going back to my default aircraft (the Trike) loading that and saving again with engine running seems to have an issues with CS 707 load up which for some reason on my PC is preferencing to no engines runnning (fine for a ramp start but a pain if you just want to do a quick fly around or check flight). When I say problem if I move from trike to 707, no engines are running, then if I select the C172 it basically loads and the engine shuts down immediately.

I am not sure but does the 707 load no engine runnings, reason I ask is that If I get out of FSX then reload the trike, the select the 727 it loads up fine with engines running etc. but it is only when I select the 707 that I get this no engines running situation. I also noted that a circuit breaker check also shows a lot of them pulled when this configuration occurs. Weird.