Adding ability to show menu button content and keep focus on it.

demo/index.html

@@ -148,6 +148,25 @@ <h4>Alternate Button</h4>
       </div>
     </div>
 
+    <div class="horizontal-section-container">
+      <div>
+        <h4>Alternate Button with visible content</h4>
+        <div class="horizontal-section">
+          <paper-menu-button show-content >
+            <paper-button class="dropdown-trigger" raised>
+              <iron-icon icon="check"></iron-icon>
+              <span>Dinosaurs</span>
+            </paper-button>
+            <paper-menu class="dropdown-content">
+              <template is="dom-repeat" items="[[dinosaurs]]" as="dinosaur">
+                <paper-item>[[dinosaur]]</paper-item>
+              </template>
+            </paper-menu>
+          </paper-menu-button>
+        </div>
+      </div>
+    </div>
+
     <div class="horizontal-section-container">
       <div>
         <h4>Alternate Content</h4>

paper-menu-button.html

@@ -91,6 +91,14 @@
         margin-top: 20px;
       }
 
+      :host([vertical-align="top"][show-content]) paper-material {
+        margin-top: 43px;
+      }
+
+      :host([vertical-align="bottom"][show-content]) paper-material {
+        margin-bottom: 43px;
+      }
+
       iron-dropdown {
         @apply(--paper-menu-button-dropdown);
       }
@@ -110,6 +118,7 @@
     <iron-dropdown
       id="dropdown"
       opened="{{opened}}"
+      no-auto-focus="[[noAutoFocus]]"
       horizontal-align="[[horizontalAlign]]"
       vertical-align="[[verticalAlign]]"
       horizontal-offset="[[horizontalOffset]]"
@@ -286,6 +295,24 @@
            */
           _dropdownContent: {
             type: Object
+          },
+          /**
+           * Set to true to keep focus on menu button element content.
+           * For example input in paper-dropdown-menu if filtering is needed. This attribute doesn't manage visibility
+           * button element content.
+           */
+          noAutoFocus: {
+            type: Boolean,
+            value: false,
+            reflectToAttribute: true
+          },
+          /**
+           * Set to true if button element content should be visible after dropdown would be  shown
+           */
+          showContent:{
+            type: Boolean,
+            value: false,
+            reflectToAttribute: true
           }
         },