have padding maintain background color.

lib/widget.js

@@ -2171,6 +2171,35 @@ outer:
     xi_ -= this.padding, xl += this.padding;
   }
 
+  if (this.padding) {
+    // Set padding to green for debugging:
+    // dattr = (dattr & ~0x1ff) | colors.convert('green');
+    // top
+    this.screen.fillRegion(dattr, ' ',
+      xi_ + (this.border ? 1 : 0),
+      xl - (this.border ? 1 : 0),
+      yi_ + (this.border ? 1 : 0),
+      yi_ + 0 + (this.border ? 1 : 0) + this.padding);
+    // bottom
+    this.screen.fillRegion(dattr, ' ',
+      xi_ + (this.border ? 1 : 0),
+      xl - (this.border ? 1 : 0),
+      yl - 0 - (this.border ? 1 : 0) - this.padding,
+      yl - (this.border ? 1 : 0));
+    // left
+    this.screen.fillRegion(dattr, ' ',
+      xi_ + (this.border ? 1 : 0),
+      xi_ + 0 + (this.border ? 1 : 0) + this.padding,
+      yi_ + (this.border ? 1 : 0),
+      yl - (this.border ? 1 : 0));
+    // right
+    this.screen.fillRegion(dattr, ' ',
+      xl - 0 - (this.border ? 1 : 0) - this.padding,
+      xl - (this.border ? 1 : 0),
+      yi_ + (this.border ? 1 : 0),
+      yl - (this.border ? 1 : 0));
+  }
+
   if (this.border) {
     yi = yi_;
     for (xi = xi_; xi < xl; xi++) {

test/widget-padding.js

@@ -11,9 +11,9 @@ blessed.box({
   align: 'center',
   left: 'center',
   top: 'center',
-  width: 20,
-  height: 8,
-  padding: 1
+  width: 22,
+  height: 10,
+  padding: 2
 });
 
 screen.key('q', function() {