Vcl.StyledComponentsHooks: first classic ShowMessage from MDI child has unusable OK button when no VCL style is active

[surfjf69]

When using Vcl.StyledComponentsHooks, standard TButton controls are replaced by TStyledButton.

If UseLatestCommonDialogs is set to False, ShowMessage uses the classic VCL dialog, which contains a TButton.
This button is then replaced by TStyledButton.

When no custom VCL style is active (Windows default style), the OK button is displayed incorrectly and is not clickable.

With a custom VCL style active, the dialog works correctly.
With UseLatestCommonDialogs=True, the issue does not occur.

This configuration is commonly used to allow Screen.MessageFont customization for MessageDlg/ShowMessage.

Additional reproduction detail:

The issue only occurs if the first classic ShowMessage is called from an MDI child form.

If a first ShowMessage is called from the MDI main form, then subsequent ShowMessage calls from the MDI child do not show the issue.

So the failing sequence is:

1. MDI application
2. No custom VCL style active
3. Vcl.StyledComponentsHooks used
4. UseLatestCommonDialogs := False
5. Open an MDI child form
6. First ShowMessage call is made from the MDI child
7. The OK button is displayed incorrectly / not clickable

Working sequence:

1. Same configuration
2. First ShowMessage is called from the MDI main form
3. Then ShowMessage from MDI child works correctly

This suggests an initialization/order issue in TStyledButton or StyledComponents when the first interposed TButton is created inside a classic VCL dialog owned by an MDI child.

[carloBarazzetta]

Please upload a simple demo to reproduce the issue, thanks.