Davo,
Thanks for the reply. No, it is i386-carbon, but that's by accident not design, I have not even thought about building the IDE as either 32 or 64 bit, thanks for the heads-up. I have an FPCUPDeluxe install as well, it is definitely x86-64-darwin-cocoa. The trunk trunk would not build, but fixes 3.2/fixes 2 does. I will reinstall that with i386 carbon if I can.
I omitted to say I used this to anchor the IDE like Delphi:
https://github.com/FlKo/LazarusDockedDesktops#how-to-installTBF, if I use the IDE NOT anchored, I do not get the same (errant) behaviour when using the form designer. So logically something in the anchoring is what is causing that strange behaviour (I didn't think to test).
WRT reporting bugs, I am loathe to do that at the moment because I don't know if what I am seeing is because of my incompetence, expected behaviour or actually a bug. At least posting to the forum I get experts like you pointing out my shortcomings (in a nice way).
And this is just to give some idea of the sorts of issues I'm experiencing: I am porting over a DYLIB and test code from Delphi. The DYLIB uses TMS FMX Cloud Pack (now TMS LCL Cloud Pack) and they are similar, but not the same (the LCL version was last updated September 2016 so TMS are not interested and they certainly have no interest if I put any of their functions in a DYLIB - what were you thinking?). Anyway TL;DR, when converting the FMX code, changing, trying a build, the Lazarus IDE just goes away, ie. I'm in the middle of something and then nothing. restart the IDE and do a bit more, IDE goes away (I haven't documented exactly what I was doing, I will).
Last but not least (and macOS/carbon/Cocoa not my area of expertise), a couple of environment questions:
1. Could I develop/build as a i386/Carbon App/DYLIB and then simply rebuild in x86_64/Cocoa when I have said software sort of working, is that viable?
2. You say you develop on Linux and use only the MAC IDE for mac specific stuff, since OSX is essentially unix/linux, is it feasible to develop on Linux for an OSX app and using the $IFDEF UNIX rather than $IFDEF DARWIN, would the code then port to OSX (other than OSX specific functions)?
Thanks for sticking with me, your advice has given me many things to try.
Kevin