diff --git a/reactos/subsys/system/taskmgr/about.c b/reactos/subsys/system/taskmgr/about.c
index 676e2cc1021..af32cc94bf7 100644
--- a/reactos/subsys/system/taskmgr/about.c
+++ b/reactos/subsys/system/taskmgr/about.c
@@ -34,7 +34,7 @@ INT_PTR CALLBACK AboutDialogWndProc(HWND hDlg, UINT message, WPARAM wParam, LPAR
 
 void OnAbout(void)
 {
-    DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hMainWnd, (DLGPROC)AboutDialogWndProc);
+    DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hMainWnd, AboutDialogWndProc);
 }
 
 INT_PTR CALLBACK
diff --git a/reactos/subsys/system/taskmgr/affinity.c b/reactos/subsys/system/taskmgr/affinity.c
index 8f6209fab05..636df36a5aa 100644
--- a/reactos/subsys/system/taskmgr/affinity.c
+++ b/reactos/subsys/system/taskmgr/affinity.c
@@ -62,7 +62,7 @@ void ProcessPage_OnSetAffinity(void)
         MessageBox(hMainWnd, strErrorText, _T("Unable to Access or Set Process Affinity"), MB_OK|MB_ICONSTOP);
         return;
     }
-    DialogBox(hInst, MAKEINTRESOURCE(IDD_AFFINITY_DIALOG), hMainWnd, (DLGPROC)AffinityDialogWndProc);
+    DialogBox(hInst, MAKEINTRESOURCE(IDD_AFFINITY_DIALOG), hMainWnd, AffinityDialogWndProc);
     if (hProcessAffinityHandle)    {
         CloseHandle(hProcessAffinityHandle);
         hProcessAffinityHandle = NULL;
diff --git a/reactos/subsys/system/taskmgr/column.c b/reactos/subsys/system/taskmgr/column.c
index ccf1f2b3d09..f1590e88681 100644
--- a/reactos/subsys/system/taskmgr/column.c
+++ b/reactos/subsys/system/taskmgr/column.c
@@ -328,7 +328,7 @@ void ProcessPage_OnViewSelectColumns(void)
 {
     int        i;
 
-    if (DialogBox(hInst, MAKEINTRESOURCE(IDD_COLUMNS_DIALOG), hMainWnd, (DLGPROC)ColumnsDialogWndProc) == IDOK)
+    if (DialogBox(hInst, MAKEINTRESOURCE(IDD_COLUMNS_DIALOG), hMainWnd, ColumnsDialogWndProc) == IDOK)
     {
         for (i=Header_GetItemCount(hProcessPageHeaderCtrl)-1; i>=0; i--)
         {
diff --git a/reactos/subsys/system/taskmgr/taskmgr.c b/reactos/subsys/system/taskmgr/taskmgr.c
index fdb58a41100..ccb3648c5da 100644
--- a/reactos/subsys/system/taskmgr/taskmgr.c
+++ b/reactos/subsys/system/taskmgr/taskmgr.c
@@ -471,13 +471,13 @@ BOOL OnCreate(HWND hWnd)
     /* Create tab pages */
     hTabWnd = GetDlgItem(hWnd, IDC_TAB);
 #if 1
-    hApplicationPage = CreateDialog(hInst, MAKEINTRESOURCE(IDD_APPLICATION_PAGE), hWnd, (DLGPROC)ApplicationPageWndProc);
-    hProcessPage = CreateDialog(hInst, MAKEINTRESOURCE(IDD_PROCESS_PAGE), hWnd, (DLGPROC)ProcessPageWndProc);
-    hPerformancePage = CreateDialog(hInst, MAKEINTRESOURCE(IDD_PERFORMANCE_PAGE), hWnd, (DLGPROC)PerformancePageWndProc);
+    hApplicationPage = CreateDialog(hInst, MAKEINTRESOURCE(IDD_APPLICATION_PAGE), hWnd, ApplicationPageWndProc);
+    hProcessPage = CreateDialog(hInst, MAKEINTRESOURCE(IDD_PROCESS_PAGE), hWnd, ProcessPageWndProc);
+    hPerformancePage = CreateDialog(hInst, MAKEINTRESOURCE(IDD_PERFORMANCE_PAGE), hWnd, PerformancePageWndProc);
 #else
-    hApplicationPage = CreateDialog(hInst, MAKEINTRESOURCE(IDD_APPLICATION_PAGE), hTabWnd, (DLGPROC)ApplicationPageWndProc);
-    hProcessPage = CreateDialog(hInst, MAKEINTRESOURCE(IDD_PROCESS_PAGE), hTabWnd, (DLGPROC)ProcessPageWndProc);
-    hPerformancePage = CreateDialog(hInst, MAKEINTRESOURCE(IDD_PERFORMANCE_PAGE), hTabWnd, (DLGPROC)PerformancePageWndProc);
+    hApplicationPage = CreateDialog(hInst, MAKEINTRESOURCE(IDD_APPLICATION_PAGE), hTabWnd, ApplicationPageWndProc);
+    hProcessPage = CreateDialog(hInst, MAKEINTRESOURCE(IDD_PROCESS_PAGE), hTabWnd, ProcessPageWndProc);
+    hPerformancePage = CreateDialog(hInst, MAKEINTRESOURCE(IDD_PERFORMANCE_PAGE), hTabWnd, PerformancePageWndProc);
 #endif
 
     /* Insert tabs */