ChatBox.cs: replace "line = new List" with "line.clear()" because it seems more efficient.

TextWindow.cs: make "TotalDisplayLines" read-only from outside (since TextWindow.cs depend soo much on "TotalDisplayLines" to not cause out-of-range exception & its already maintained internally & no code uses it yet, so its good to be read-only)

ChatControl.Designer.cs & BattleBar.Designer.cs & TextColoringPanel.Designer.cs: remove external initialization of "TotalDisplayLines" property.