Add middle and right mouse button actions to asset/object pickers to clear value or show popup quickly

Source/Editor/CustomEditors/Editors/FlaxObjectRefEditor.cs

@@ -322,7 +322,11 @@ namespace FlaxEditor.CustomEditors.Editors
 
             // Deselect
             if (_value != null && button1Rect.Contains(ref location))
+            {
+                Focus();
                 Value = null;
+                return true;
+            }
 
             // Picker dropdown menu
             if (_supportsPickDropDown && (isSelected ? button2Rect : button1Rect).Contains(ref location))
@@ -372,6 +376,18 @@ namespace FlaxEditor.CustomEditors.Editors
                 if (_hasValidDragOver)
                     _hasValidDragOver = false;
             }
+            if (button == MouseButton.Middle)
+            {
+                // Clear value
+                Focus();
+                Value = null;
+                return true;
+            }
+            if (button == MouseButton.Right && _supportsPickDropDown)
+            {
+                // Show picker
+                ShowDropDownMenu();
+            }
 
             return base.OnMouseUp(location, button);
         }

Source/Editor/GUI/AssetPicker.cs

@@ -299,6 +299,7 @@ namespace FlaxEditor.GUI
                 }
                 else if (Button1Rect.Contains(location))
                 {
+                    // Show picker
                     Focus();
                     OnSubmit();
                 }
@@ -318,6 +319,18 @@ namespace FlaxEditor.GUI
                     }
                 }
             }
+            if (button == MouseButton.Middle && IconRect.Contains(ref location))
+            {
+                // Clear value
+                Focus();
+                Validator.SelectedItem = null;
+            }
+            if (button == MouseButton.Right && IconRect.Contains(ref location))
+            {
+                // Show picker
+                Focus();
+                OnSubmit();
+            }
 
             // Handled
             return true;