TextBox editing improvements

1. When you create new TextBox (or other element), it's nice if it's already selected.
2. When there's selected textbox (not in editing mode), if you start typing in it, it's nice if it accepts your input right away, without you double-clicking to enter editing mode.
3. When doubleclick a textbox, it's nice if all text inside textbox would be selected by default. This way you can use etch buttons right away (right now you need to select some text manually).