TStyledToolbar.ChangeScale is not compatible with ScaleBy (cumulative scaling issue) #94
Description
I identified a structural issue in TStyledToolbar.ChangeScale.
The current implementation applies cumulative scaling:
FButtonWidth := MulDiv(FButtonWidth, M, D);
FButtonHeight := MulDiv(FButtonHeight, M, D);
However, ChangeScale can be called multiple times during a control’s lifecycle (MDI layout changes, parent scaling, alignment recalculations, DPI changes, etc.).
When ScaleBy is used, this leads to exponential growth of button sizes (for example, ButtonWidth growing from 48 to 149), even when:
AutoSize is disabled
no ImageList is assigned
By contrast, the standard VCL TToolBar and TStyledButton do not perform cumulative scaling; they recalculate metrics from a base value (or only react to real DPI changes via isDpiChange), which keeps them stable.
Conclusion
TStyledToolbar is not compatible with ScaleBy by design due to cumulative scaling in ChangeScale.