Yep, I thoroughly tried to find where TChart design time has gone, or at least, tried to understand what is going on, but no luck, alas.
Here is what is filtered in IDE ToolPalette for FMX, when typing "tchart":

- "tchart" filtered in ToolPalette
- tchart2.jpg (6.24 KiB) Viewed 14891 times
Another obvious sign that design time component is missing - existing projects, which contained forms with TChart will not load form designer with error, like: "TChart component is unknown, Ignore - delete component, Cancel - abort form designer loading".
What is more, comparing your screenshot with mine, it occurred, that in my case there are no ListBox, EditorPanel, GalleryPanel, Grid components (assuming your example is taken in FMX environment as well).
PS. I've tried to fully uninstall TeeChartPro, restored Lite component in IDE. Then, re-installed Pro FullSource, with the same result.
PPS. Binary Pro installer gives the same result - no TChart design time. There might be something, preventing it from loading, but I do not know what it is. Are there some other IDE components to be loaded as well, which are the requirement for TChart design time to load?
PPPS. Interesting. From IDE packages manager, I've removed TeChart Pro VCL packages, and then - surprise, surprise! FMX TChart design time is loaded, at last, and many other FMX Tee design time components appeared in ToolPalette. As soon as mainstream projects in out development group are targeted for FireMonkey, this work-aroung is just fine. As for "who's responsible" question - htere are two possibilities. Either C++ Builder package manager is unable to distinguish between VCL and FMX packages under corresponding project environments, when both loaded at the same time. Or TeeChart VCL|FMX design time packages conflicts with each other, when loaded at the same time.