Question: During compilation of the project, a message shows ‘ Class TfrxButtonControl not found'.

Answer:

Add the component TfrxDialogControls (TfrxRichObject, TfrxCrossObject, TfrxOLEObject, TfrxBarCodeObject, TfrxCheckBoxObject, TfrxGradientObject, frxChartObject, TfrxADOComponents, etc.) from FR component panel into the project or add in the uses section the following modules: frxDCtrl, frxRich, frxCross, frxOLE, frxBarcode, frxChBox, frxGradient, frxChart, frxADOComponents.