support for .NET framework 3.5

Still have bugs

Net35/HandyControl_Net35/Shell/Standard/STATE_SYSTEM.cs

@@ -0,0 +1,42 @@
+namespace Standard
+{
+    using System;
+
+    [Flags]
+    internal enum STATE_SYSTEM
+    {
+        ALERT_HIGH = 0x10000000,
+        ALERT_LOW = 0x4000000,
+        ALERT_MEDIUM = 0x8000000,
+        ANIMATED = 0x4000,
+        BUSY = 0x800,
+        CHECKED = 0x10,
+        COLLAPSED = 0x400,
+        DEFAULT = 0x100,
+        EXPANDED = 0x200,
+        EXTSELECTABLE = 0x2000000,
+        FLOATING = 0x1000,
+        FOCUSABLE = 0x100000,
+        FOCUSED = 4,
+        HOTTRACKED = 0x80,
+        INDETERMINATE = 0x20,
+        INVISIBLE = 0x8000,
+        LINKED = 0x400000,
+        MARQUEED = 0x2000,
+        MIXED = 0x20,
+        MOVEABLE = 0x40000,
+        MULTISELECTABLE = 0x1000000,
+        OFFSCREEN = 0x10000,
+        PRESSED = 8,
+        PROTECTED = 0x20000000,
+        READONLY = 0x40,
+        SELECTABLE = 0x200000,
+        SELECTED = 2,
+        SELFVOICING = 0x80000,
+        SIZEABLE = 0x20000,
+        TRAVERSED = 0x800000,
+        UNAVAILABLE = 1,
+        VALID = 0x3fffffff
+    }
+}
+