When executing the call to this procedure, it causes an exception by not having assigned a TAG value in the following atb: = AddButton (...
atb: = AddButton (HInstance, TAdvRichEditorBold, bsCheck, 'TMSRETBBOLD', 'Bold');
atb.Tag: = integer (btBold); <----------------
atb: = AddButton (HInstance, TAdvRichEditorItalic, bsCheck, 'TMSRETBITALIC', 'Italic');
atb.Tag: = integer (btItalic); <----------------
atb: = AddButton (HInstance, TAdvRichEditorUnderline, bsCheck, 'TMSRETBUNDERLINE', 'Underline');
atb.Tag: = integer (btUnderline); <----------------
atb: = AddButton (HInstance, TAdvRichEditorStrikeout, bsCheck, 'TMSRETBSTRIKE', 'Strikeout');
atb.Tag: = integer (btStrikeThrough); <----------------
atb: = AddButton (HInstance, TAdvRichEditorSubScript, bsCheck, 'TMSRETBSUBSCR', 'SubScript');
atb.Tag: = integer (btSubscript); <----------------
atb: = AddButton (HInstance, TAdvRichEditorSuperScript, bsCheck, 'TMSRETBSUPERSCR', 'SuperScript');
atb.Tag: = integer (btSuperscript); <----------------