Fix interaction between mouse and keyboard (#3070)

core/gesture.js

@@ -663,6 +663,9 @@ Blockly.Gesture.prototype.handleWsStart = function(e, ws) {
   this.setStartWorkspace_(ws);
   this.mostRecentEvent_ = e;
   this.doStart(e);
+  if (Blockly.keyboardAccessibilityMode) {
+    Blockly.navigation.setState(Blockly.navigation.STATE_WS);
+  }
 };
 
 /**

core/keyboard_nav/navigation.js

@@ -107,6 +107,15 @@ Blockly.navigation.removeMark_ = function() {
   Blockly.getMainWorkspace().getMarker().hide();
 };
 
+/**
+ * Set the current navigation state.
+ * @param {number} newState The new navigation state.
+ * @package
+ */
+Blockly.navigation.setState = function(newState) {
+  Blockly.navigation.currentState_ = newState;
+};
+
 /**
  * Gets the top node on a block.
  * This is either the previous connection, output connection or the block.
@@ -133,20 +142,23 @@ Blockly.navigation.getTopNode = function(block) {
 /************************/
 
 /**
- * Set the state to the toolbox state and the current category as the first
+ * If a toolbox exists, set the navigation state to toolbox and select the first
+ * category in the toolbox.
  * category.
  * @private
  */
 Blockly.navigation.focusToolbox_ = function() {
-  Blockly.navigation.resetFlyout_(false /* shouldHide */);
-  Blockly.navigation.currentState_ = Blockly.navigation.STATE_TOOLBOX;
   var workspace = Blockly.getMainWorkspace();
   var toolbox = workspace.getToolbox();
+  if (toolbox) {
+    Blockly.navigation.currentState_ = Blockly.navigation.STATE_TOOLBOX;
+    Blockly.navigation.resetFlyout_(false /* shouldHide */);
 
-  if (!Blockly.getMainWorkspace().getMarker().getCurNode()) {
-    Blockly.navigation.markAtCursor_();
+    if (!Blockly.getMainWorkspace().getMarker().getCurNode()) {
+      Blockly.navigation.markAtCursor_();
+    }
+    toolbox.selectFirstCategory();
   }
-  toolbox.selectFirstCategory();
 };
 
 /***********************/

core/toolbox.js

@@ -260,9 +260,15 @@ Blockly.Toolbox.prototype.handleAfterTreeSelected_ = function(
     if (this.lastCategory_ != newNode) {
       this.flyout_.scrollToStart();
     }
+    if (Blockly.keyboardAccessibilityMode) {
+      Blockly.navigation.setState(Blockly.navigation.STATE_TOOLBOX);
+    }
   } else {
     // Hide the flyout.
     this.flyout_.hide();
+    if (Blockly.keyboardAccessibilityMode) {
+      Blockly.navigation.setState(Blockly.navigation.STATE_WS);
+    }
   }
   if (oldNode != newNode && oldNode != this) {
     var event = new Blockly.Events.Ui(null, 'category',