diff --git a/redo/windows/GNUmakeinc.mk b/redo/windows/GNUmakeinc.mk
index ba7fb5ed..81331122 100644
--- a/redo/windows/GNUmakeinc.mk
+++ b/redo/windows/GNUmakeinc.mk
@@ -9,6 +9,7 @@ osCFILES = \
 	windows/control.c \
 	windows/datetimepicker.c \
 	windows/debug.c \
+	windows/dialoghelper.c \
 	windows/entry.c \
 	windows/events.c \
 	windows/group.c \
diff --git a/redo/windows/dialoghelper.c b/redo/windows/dialoghelper.c
new file mode 100644
index 00000000..584247c6
--- /dev/null
+++ b/redo/windows/dialoghelper.c
@@ -0,0 +1,110 @@
+// 22 may 2015
+#include "uipriv_windows.h"
+
+// see http://stackoverflow.com/questions/25494914/is-there-something-like-cdn-filecancel-analogous-to-cdn-fileok-for-getting-when#comment40420049_25494914
+
+// TODO reconcile this with users being able to enable/disable windows
+
+struct dialogDisableWindow {
+	HWND hwnd;
+	uintmax_t n;
+	UT_hash_handle hh;
+};
+
+static struct dialogDisableWindow *windows = NULL;
+
+void dialogHelperRegisterWindow(HWND hwnd)
+{
+	struct dialogDisableWindow *d;
+
+	HASH_FIND_PTR(windows, &hwnd, d);
+	if (d != NULL)
+		complain("window handle %p already register in dialogHelperRegisterWindow()", hwnd);
+	d = uiNew(struct dialogDisableWindow);
+	d->hwnd = hwnd;
+	HASH_ADD_PTR(windows, hwnd, d);
+}
+
+void dialogHelperUnregisterWindow(HWND hwnd)
+{
+	struct dialogDisableWindow *d;
+
+	HASH_FIND_PTR(windows, &hwnd, d);
+	if (d == NULL)
+		complain("window handle %p not registered in dialogHelperUnregisterWindow()", hwnd);
+	HASH_DEL(windows, d);
+	uiFree(d);
+}
+
+static void dialogBegin(void)
+{
+	struct dialogDisableWindow *d;
+
+	for (d = windows; d != NULL; d = d->hh.next) {
+		EnableWindow(d->hwnd, FALSE);
+		d->n++;
+	}
+}
+
+static void dialogEnd(void)
+{
+	struct dialogDisableWindow *d;
+
+	for (d = windows; d != NULL; d = d->hh.next) {
+		d->n--;
+		if (d->n == 0)
+			EnableWindow(d->hwnd, TRUE);
+	}
+}
+
+#define dialogHelperClass L"libui_dialogHelperClass"
+
+static LRESULT CALLBACK dialogHelperWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
+{
+	switch (uMsg) {
+	case WM_CREATE:
+		dialogBegin();
+		break;
+	case WM_ENABLE:
+		if (wParam != (WPARAM) FALSE)		// enabling
+			dialogEnd();
+		break;
+	}
+	return DefWindowProcW(hwnd, uMsg, wParam, lParam);
+}
+
+ATOM initDialogHelper(HICON hDefaultIcon, HCURSOR hDefaultCursor)
+{
+	WNDCLASSW wc;
+
+	ZeroMemory(&wc, sizeof (WNDCLASSW));
+	wc.lpszClassName = dialogHelperClass;
+	wc.lpfnWndProc = dialogHelperWndProc;
+	wc.hInstance = hInstance;
+	wc.hIcon = hDefaultIcon;
+	wc.hCursor = hDefaultCursor;
+	wc.hbrBackground = (HBRUSH) (COLOR_BTNFACE + 1);
+	return RegisterClassW(&wc);
+}
+
+uintptr_t beginDialogHelper(void)
+{
+	HWND hwnd;
+
+	hwnd = CreateWindowExW(0,
+		dialogHelperClass, L"libui dialog helper",
+		WS_OVERLAPPEDWINDOW,
+		0, 0, 100, 100,
+		NULL, NULL, hInstance, NULL);
+	if (hwnd == NULL)
+		logLastError("error creating dialog helper in beginDialogHelper()");
+	return (uintptr_t) hwnd;
+}
+
+void endDialog(uintptr_t handle)
+{
+	HWND hwnd = (HWND) handle;
+
+	if (DestroyWindow(hwnd) == 0)
+		logLastError("error cleaning up after dialog helper in endDialogHelper()");
+}
diff --git a/redo/windows/init.c b/redo/windows/init.c
index 9009d953..9dc1604b 100644
--- a/redo/windows/init.c
+++ b/redo/windows/init.c
@@ -141,6 +141,9 @@ const char *uiInit(uiInitOptions *o)
 	if (InitCommonControlsEx(&icc) == 0)
 		return loadLastError("initializing Common Controls");
 
+	if (initDialogHelper(hDefaultIcon, hDefaultCursor) == 0)
+		return loadLastError("initializing the dialog helper");
+
 	return NULL;
 }
 
diff --git a/redo/windows/uipriv_windows.h b/redo/windows/uipriv_windows.h
index c7ad1a55..0cbf71b3 100644
--- a/redo/windows/uipriv_windows.h
+++ b/redo/windows/uipriv_windows.h
@@ -120,3 +120,10 @@ extern void uiWindowsUnregisterWM_HSCROLLHandler(HWND);
 extern BOOL runWM_COMMAND(WPARAM, LPARAM, LRESULT *);
 extern BOOL runWM_NOTIFY(WPARAM, LPARAM, LRESULT *);
 extern BOOL runWM_HSCROLL(WPARAM, LPARAM, LRESULT *);
+
+// dialoghelper.c
+extern void dialogHelperRegisterWindow(HWND);
+extern void dialogHelperUnregisterWindow(HWND);
+extern ATOM initDialogHelper(HICON, HCURSOR);
+extern uintptr_t beginDialogHelper(void);
+extern void endDialog(uintptr_t);
diff --git a/redo/windows/window.c b/redo/windows/window.c
index ad6ce836..9f578fd4 100644
--- a/redo/windows/window.c
+++ b/redo/windows/window.c
@@ -97,6 +97,7 @@ static void windowDestroy(uiControl *c)
 	if (w->menubar != NULL)
 		freeMenubar(w->menubar);
 	// and finally destroy ourselves
+	dialogHelperUnregisterWindow(w->hwnd);
 	if (DestroyWindow(w->hwnd) == 0)
 		logLastError("error destroying uiWindow in windowDestroy()");
 	uiFree(w);
@@ -351,6 +352,8 @@ uiWindow *uiNewWindow(const char *title, int width, int height, int hasMenubar)
 		logLastError("error creating window in uiWindow()");
 	uiFree(wtitle);
 
+	dialogHelperRegisterWindow(w->hwnd);
+
 	if (hasMenubar) {
 		w->menubar = makeMenubar();
 		if (SetMenu(w->hwnd, w->menubar) == 0)