diff --git a/theme.go b/theme.go
index 2de60ab..a0e1aa6 100644
--- a/theme.go
+++ b/theme.go
@@ -59,7 +59,7 @@ func NewThemeManager() *ThemeManager {
 	defTheme.colors[ColorDisabledText] = ColorBlackBold
 	defTheme.colors[ColorDisabledBack] = ColorWhite
 	defTheme.colors[ColorText] = ColorWhite
-	defTheme.colors[ColorBack] = ColorBlack
+	defTheme.colors[ColorBack] = ColorBlackBold
 	defTheme.colors[ColorViewBack] = ColorBlackBold
 	defTheme.colors[ColorViewText] = ColorWhite
 
diff --git a/window.go b/window.go
index 3db39ef..c2d1023 100644
--- a/window.go
+++ b/window.go
@@ -35,17 +35,25 @@ func NewWindow(parent Screen, x, y, w, h int, title string) *Window {
 }
 
 func (w *Window) SetSize(width, height int) {
-	if width > 1000 || width < w.minW {
+	if width == w.width && height == w.height {
+		return
+	}
+
+	if width != DoNotChange && (width > 1000 || width < w.minW) {
 		panic(fmt.Sprintf("Invalid width: %v", width))
 	}
-	if height > 200 || height < w.minH {
+	if height != DoNotChange && (height > 200 || height < w.minH) {
 		panic(fmt.Sprintf("Invalid height: %v", height))
 	}
 
-	w.width = width
-	w.height = height
+	if width != DoNotChange {
+		w.width = width
+	}
+	if height != DoNotChange {
+		w.height = height
+	}
 
-	w.canvas.SetSize(width, height)
+	w.canvas.SetSize(w.width, w.height)
 	RepositionControls(0, 0, w)
 }