@JonB And there it is...and indeed pretty obvious, but I missed it.

Thank you so much!

Well, I guess the bigger issue here is that it's worth reading though the modules that @omz has provided in Python. Some other useful stuff can be found.

https://github.com/jsbain/objc_hacks with a "c" on the objc

@TutorialDoctor , you are welcome to use any of it you want. As I say, I am mainly just putting together other people's work. It's been published on the forum before in simlar ways. I just try to,acknowledge them when I know we're it comes from. So as far as I can see its ok to use it.
I have taken that to be the general common sense rule here.

Yeah. I haven't tested my repo on these custom themes specifically, but it worked on the old kind

@JonB I mentioned that as a known issue a while back (first beta, I think), it's still on my todo list.

Note to self (and others so afflicted)—
Starting with this seemed to fix it:
set_fill_color(1.0,1.0,1.0)
fill_rect(0,0,scrSize[0],scrSize[1])

where i've done this at global scope:
scrSize=(1136,640) # iPhone 5
set_size(*scrSize) # min 16, max 2048

(my canvas is meant for landscape viewing)

@Phuket2
You control your destiny. Ask Jesus for forgiveness. He forgives all sin we confess. Believe in him. When Jesus forgives us, anything we have done in the past is gone and forgotten. Only our own guilt will prevent us from enjoying everything He has given us.
"Jesus replied, 'Very truly I tell you, no one can see the kingdom of God unless they are born again.'"-NIV Bible John 3:3.
"For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life. For God did not send his Son into the world to condemn the world, but to save the world through him. Whoever believes in him is not condemned, but whoever does not believe stands condemned already because they have not believed in the name of God’s one and Son."-NIV Bible, John 3:16-18.
Thanks for the help.