diff --git a/lcl/dialogs.pp b/lcl/dialogs.pp
index 4bbbff061b..44cad94e12 100644
--- a/lcl/dialogs.pp
+++ b/lcl/dialogs.pp
@@ -627,7 +627,7 @@ type
     FButton: TTaskDialogButtonItem;
     FButtons: TTaskDialogButtons;
     FCaption: TTranslateString;
-    FCollapsButtonCaption: TTranslateString;
+    FCollapseButtonCaption: TTranslateString;
     FCommonButtons: TTaskDialogCommonButtons;
     FDefaultButton: TTaskDialogCommonButton;
     FExpandButtonCaption: TTranslateString;
@@ -694,7 +694,7 @@ type
     property Buttons: TTaskDialogButtons read FButtons write SetButtons;
     property Caption: TTranslateString read FCaption write FCaption;
     property CommonButtons: TTaskDialogCommonButtons read FCommonButtons write FCommonButtons default [tcbOk, tcbCancel];
-    property CollapsButtonCaption: TTranslateString read FCollapsButtonCaption write FCollapsButtonCaption;
+    property CollapseButtonCaption: TTranslateString read FCollapseButtonCaption write FCollapseButtonCaption;
     property DefaultButton: TTaskDialogCommonButton read FDefaultButton write FDefaultButton default tcbOk;
     property ExpandButtonCaption: TTranslateString read FExpandButtonCaption write FExpandButtonCaption;
     property ExpandedText: TTranslateString read FExpandedText write FExpandedText;
@@ -734,7 +734,7 @@ type
     property Buttons;
     property Caption;
     property CommonButtons;
-    property CollapsButtonCaption;
+    property CollapseButtonCaption;
     property DefaultButton;
     property ExpandButtonCaption;
     property ExpandedText;
diff --git a/lcl/interfaces/win32/win32wsdialogs.pp b/lcl/interfaces/win32/win32wsdialogs.pp
index 9475844cb3..fe829e5afb 100644
--- a/lcl/interfaces/win32/win32wsdialogs.pp
+++ b/lcl/interfaces/win32/win32wsdialogs.pp
@@ -1864,7 +1864,7 @@ var
     end;
     ExpandedInformation := Utf8ToUtf16(ADlg.ExpandedText);
     CollapsedControlText := Utf8ToUtf16(ADlg.ExpandButtonCaption);
-    ExpandedControlText := Utf8ToUtf16(ADlg.CollapsButtonCaption);
+    ExpandedControlText := Utf8ToUtf16(ADlg.CollapseButtonCaption);
 
     Footer := Utf8ToUtf16(ADlg.FooterText);
 
diff --git a/lcl/taskdlgemulation.pp b/lcl/taskdlgemulation.pp
index 0216e31323..4f0c24dcb7 100644
--- a/lcl/taskdlgemulation.pp
+++ b/lcl/taskdlgemulation.pp
@@ -39,7 +39,7 @@ type
 
     //CustomButtons, Radios: TStringList;
     DialogCaption, DlgTitle, DlgText,
-    ExpandButtonCaption, CollapsButtonCaption, ExpandedText, FooterText,
+    ExpandButtonCaption, CollapseButtonCaption, ExpandedText, FooterText,
     VerificationText: String;
     CommonButtons: TTaskDialogCommonButtons;
 
@@ -53,7 +53,7 @@ type
     QueryEdit: TEdit;
     /// the Task Dialog optional checkbox
     VerifyCheckBox: TCheckBox;
-    /// the Expand/Collaps button
+    /// the Expand/Collapse button
     ExpandBtn: TButton;
 
     procedure GetDefaultButtons(out aButtonDef, aRadioDef: TModalResult);
@@ -74,7 +74,7 @@ type
     procedure SetupTimer;
     procedure ResetTimer;
     procedure ExpandDialog;
-    procedure CollapsDialog;
+    procedure CollapseDialog;
 
     procedure DoDialogConstructed;
     procedure DoDialogCreated;
@@ -343,7 +343,7 @@ begin
   DlgTitle := FDlg.Title;
   DlgText := FDlg.Text;
   ExpandButtonCaption := FDlg.ExpandButtonCaption;
-  CollapsButtonCaption := FDlg.CollapsButtonCaption;
+  CollapseButtonCaption := FDlg.CollapseButtonCaption;
   ExpandedText := FDlg.ExpandedText;
   FooterText := FDlg.FooterText;
   VerificationText := FDlg.VerificationText;
@@ -612,18 +612,18 @@ begin
   CurrTabOrder := Panel.TabOrder;
   if (ExpandButtonCaption = '') then
   begin
-    if (CollapsButtonCaption = '') then
+    if (CollapseButtonCaption = '') then
     begin
       //ToDo: make this a resourcestring in LCLStrConsts unit
       ExpandButtonCaption := 'Show details';
-      CollapsButtonCaption := 'Hide details';
+      CollapseButtonCaption := 'Hide details';
     end
     else
-      ExpandButtonCaption := CollapsButtonCaption;
+      ExpandButtonCaption := CollapseButtonCaption;
   end;
-  if (CollapsButtonCaption = '') then
-    CollapsButtonCaption := ExpandButtonCaption;
-  WB := Max(Canvas.TextWidth(ExpandButtonCaption), Canvas.TextWidth(CollapsButtonCaption)) +32;//52;
+  if (CollapseButtonCaption = '') then
+    CollapseButtonCaption := ExpandButtonCaption;
+  WB := Max(Canvas.TextWidth(ExpandButtonCaption), Canvas.TextWidth(CollapseButtonCaption)) +32;//52;
   if (ALeft+WB > XB) then
   begin
     inc(ATop,32);
@@ -640,7 +640,7 @@ begin
   if not (tfExpandedByDefault in FDlg.Flags) then
     ExpandBtn.Caption := ExpandButtonCaption
   else
-    ExpandBtn.Caption := CollapsButtonCaption;
+    ExpandBtn.Caption := CollapseButtonCaption;
   ExpandBtn.ModalResult := mrNone;
   ExpandBtn.TabOrder := CurrTabOrder;
   ExpandBtn.OnClick := @OnExpandButtonClicked;
@@ -779,7 +779,7 @@ begin
   if not FExpanded then
     ExpandDialog
   else
-    CollapsDialog;
+    CollapseDialog;
   FExpanded := not FExpanded;
   {$PUSH}
   {$ObjectChecks OFF}
@@ -847,10 +847,10 @@ begin
   //ToDo: actually expand the dialog
 end;
 
-procedure TLCLTaskDialog.CollapsDialog;
+procedure TLCLTaskDialog.CollapseDialog;
 begin
-  ExpandBtn.Caption := CollapsButtonCaption;
-  //ToDo: actually collaps the dialog
+  ExpandBtn.Caption := CollapseButtonCaption;
+  //ToDo: actually collapse the dialog
 end;
 
 procedure TLCLTaskDialog.DoDialogConstructed;