Expected. Inbox messages are never deleted while you are logged in, so it’s possible to see previous+current day together.
Changed in v.118 
Idea
Yes, but to prevent abuse you’d also have to limit the amount purchased while on sale, which is messy.
It’s intended.
This. If there was a benefit to selling larger quantities, then that would encourage hoarding it (which is not desired).
This is because there was something wrong with your slots. This has been happening (rarely) for months now, but I haven’t pinned down what’s causing it. Probably something related to drag-dropping and/or using “unmount all”. If you notice any particular action (or sequence of actions) that always triggers it, please let me know.
A bit cluttered. Also, would that red text would be visible only if you have an active Keys Insight? Or all the time?
It could be done, but I find it poor UX to warp the mouse pointer around. It’s bad enough I have to do it in “capture mouse pointer” mode.
Time can’t simply advance for one player separately from the rest – it would be very confusing since their clocks would no longer agree.
It works for me. But you need to slightly delay the second tap – if you press both too close together, the game will only register it as a single tap.
In any case, it’s not worth ‘fixing’.
This is because the extra health spawned by the ejected ‘pilot’ actually reduces your completion percentage
Can’t change. The bubble size is automatically calculated based on the hitbox of each enemy.
Yes, but they don’t make that much of a difference.
Dropping coins is an ugly hack in the code, I’d rather not do it again.
I can’t reset assignments without deleting them from your mission history, which (as discussed elsewhere about Key Rushes) would mess up your % mission completion in the Galaxy’s Information Overlay.