diff --git a/control_base.go b/control_base.go
index 3fe24e1..39ee185 100644
--- a/control_base.go
+++ b/control_base.go
@@ -79,10 +79,10 @@ func (c *ControlBase) SetPos(x, y int) {
 	c.y = y
 }
 
-// ApplyConstraints checks if the current size fits minimal size.
+// applyConstraints checks if the current size fits minimal size.
 // Contol size is increased if its size is less than the current
 // contol minimal size
-func (c *ControlBase) ApplyConstraints() {
+func (c *ControlBase) applyConstraints() {
 	w, h := c.Size()
 	wM, hM := c.Constraints()
 
@@ -110,7 +110,7 @@ func (c *ControlBase) SetConstraints(width, height int) {
 		c.minH = height
 	}
 
-	c.ApplyConstraints()
+	c.applyConstraints()
 }
 
 // Constraints return minimal control widht and height
diff --git a/interface.go b/interface.go
index 041bc98..19045ea 100644
--- a/interface.go
+++ b/interface.go
@@ -112,11 +112,25 @@ type View interface {
 }
 
 type Control interface {
+	// Title returns the current title or text of the control
 	Title() string
+	// SetTitle changes control text or title
 	SetTitle(string)
+	// Pos returns the current control position: X and Y.
+	// For View the position's origin is top left corner of console window,
+	// for other controls the origin is top left corner of View that hold
+	// the control
 	Pos() (int, int)
+	// SetPos changes contols position. Manual call of the method does not
+	// make sense for any control except View because control positions
+	// inside of container always recalculated after View resizes
 	SetPos(int, int)
+	// Size returns current control width and height
 	Size() (int, int)
+	// SetSize changes control size. Constant DoNotChange can be
+	// used as placeholder to indicate that the control attrubute
+	// should be unchanged.
+	// Method panics if new size is less than minimal size
 	SetSize(int, int)
 	Scale() int
 	SetScale(int)
diff --git a/window.go b/window.go
index a7a3064..1b6958b 100644
--- a/window.go
+++ b/window.go
@@ -67,7 +67,7 @@ func (w *Window) SetSize(width, height int) {
 	RepositionControls(0, 0, w)
 }
 
-func (w *Window) ApplyConstraints() {
+func (w *Window) applyConstraints() {
 	width, height := w.Size()
 	wM, hM := w.Constraints()
 
@@ -92,7 +92,7 @@ func (w *Window) SetConstraints(width, height int) {
 		w.minH = height
 	}
 
-	w.ApplyConstraints()
+	w.applyConstraints()
 }
 
 func (w *Window) Draw(canvas Canvas) {