diff --git a/redo/box.c b/redo/box.c
index 5888383a..6dba03ba 100644
--- a/redo/box.c
+++ b/redo/box.c
@@ -267,8 +267,6 @@ static void boxDelete(uiBox *ss, uintmax_t index)
 	struct boxControl *bc;
 	uiControl *removed;
 
-	// TODO rearrange this
-	// TODO sync call order with that of Destroy()
 	bc = ptrArrayIndex(b->controls, struct boxControl *, index);
 	removed = bc->c;
 	ptrArrayDelete(b->controls, index);
diff --git a/redo/ui.idl b/redo/ui.idl
index 5b6188bb..864fad0e 100644
--- a/redo/ui.idl
+++ b/redo/ui.idl
@@ -158,7 +158,7 @@ func NewGroup(text *const char) *Group;
 // spinbox/slider rules:
 // setting value outside of range will automatically clamp
 // initial value is minimum
-// TODO what happens if max > min? max == min?
+// complaint if min >= max?
 
 interface Spinbox from Control {
 	func Value(void) intmax_t;
diff --git a/redo/windows/spinbox.c b/redo/windows/spinbox.c
index 54beb030..eed5e80f 100644
--- a/redo/windows/spinbox.c
+++ b/redo/windows/spinbox.c
@@ -218,6 +218,9 @@ uiSpinbox *uiNewSpinbox(intmax_t min, intmax_t max)
 {
 	struct spinbox *s;
 
+	if (min >= max)
+		complain("error: min >= max in uiNewSpinbox()");
+
 	s = (struct spinbox *) uiNewControl(uiTypeSpinbox());
 
 	s->hwnd = uiWindowsUtilCreateControlHWND(WS_EX_CLIENTEDGE,