Why does the Component Palette change when I open a data module?

Question

I installed Delphi 7 on Windows 7 x64. Things went well for while, but now, when I open or create a data module it messes up the component palette. By messes up, I mean it seems to scramble which tabs components are on, or hide them altogether. This is really unusual behaviour.

Uninstalling and reinstalling Delphi 7 hasn't helped.

Delphi 7 is about 10 years old. Are you only just noticing this behavior now? — Rob Kennedy, Sep 10 '13 at 19:08
Related [not duplicate]: http://stackoverflow.com/questions/14097246/delphi-xe2-data-module-expects-only-database-components — Jerry Dodge, Sep 10 '13 at 20:57
@RobKennedy, it's even older now, and still works like a charm. :) — Robatron, Jan 20 '21 at 07:27

Ken White · Accepted Answer · 2013-09-10T18:55:56.120

The component palette is context sensitive, so that tabs that can't be used aren't displayed. (Visual components make no sense in a datamodule, because you can't put a visual component on a datamodule. There's no point in showing you components you can't use.) A tab that has only visual components on it will be totally hidden; if there is a mix of visual and non-visual components (like the Win32 tab), only the non-visual components will be displayed.

Switching to the design window for a form should display both visual and non-visual components, including making those hidden tabs visible again.

Why does the Component Palette change when I open a data module?

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