remove _isScreen.

lib/widget.js

@@ -41,7 +41,7 @@ function Node(options) {
 
   (options.children || []).forEach(this.append.bind(this));
 
-  if (this._isScreen && !this.focused) {
+  if (this.type === 'screen' && !this.focused) {
     this.focused = this.children[0];
   }
 
@@ -67,7 +67,7 @@ Node.prototype.prepend = function(element) {
   element.detach();
   element.parent = this;
 
-  if (this._isScreen && !this.focused) {
+  if (this.type === 'screen' && !this.focused) {
     this.focused = element;
   }
 
@@ -96,7 +96,7 @@ Node.prototype.append = function(element) {
   element.detach();
   element.parent = this;
 
-  if (this._isScreen && !this.focused) {
+  if (this.type === 'screen' && !this.focused) {
     this.focused = element;
   }
 
@@ -127,14 +127,14 @@ Node.prototype.remove = function(element) {
     this.children.splice(i, 1);
   }
 
-  if (!this._isScreen) {
+  if (this.type !== 'screen') {
     i = this.screen.clickable.indexOf(element);
     if (~i) this.screen.clickable.splice(i, 1);
     i = this.screen.input.indexOf(element);
     if (~i) this.screen.input.splice(i, 1);
   }
 
-  if (this._isScreen && this.focused === element) {
+  if (this.type === 'screen' && this.focused === element) {
     this.focused = this.children[0];
   }
 
@@ -238,7 +238,6 @@ function Screen(options) {
 
   Node.call(this, options);
 
-  this._isScreen = true;
   this.program = options.program;
   this.tput = this.program.tput;
   this.dattr = ((0 << 18) | (0x1ff << 9)) | 0x1ff;
@@ -1091,7 +1090,7 @@ Element.prototype.__defineGetter__('visible', function() {
 Element.prototype.__defineGetter__('detached', function() {
   var el = this;
   do {
-    if (el._isScreen) return false;
+    if (el.type === 'screen') return false;
     if (!el.parent) return true;
   } while (el = el.parent);
   return false;