Fixes #1, causes #4

Fixes window resize affecting child windows.
Commit is for the best, but stops scrollbars showing on load until
resized.

CGui.ahk

@@ -73,10 +73,18 @@ class _CScrollGui extends _CGui {
 		OnMessage(WM_SIZE, fn, 999)
 	}
 
-	AdjustToParent(){
+	; AKA Window resized.
+	AdjustToParent(WParam:= 0, lParam := 0, Msg := 0, hwnd := 0){
 		Static SB_HORZ := 0, SB_VERT = 1
 		static SIF_PAGE := 0x2
 
+		if (hwnd = 0){
+			hwnd := this._hwnd
+		} else if (this._hwnd != hwnd){
+			; message not for this window
+			return
+		}
+		tooltip % this._hwnd
 		WindowRECT := this._GetClientRect()
 		CanvasRECT := this._GetClientSize()
 		Width := WindowRECT.Right
@@ -117,10 +125,18 @@ class _CScrollGui extends _CGui {
 		}
 	}
 
-	AdjustToChild(){
+	; AKA Child contents changed size
+	AdjustToChild(WParam := 0, lParam := 0, msg := 0, hwnd := 0){
 		Static SB_HORZ := 0, SB_VERT = 1
 		static SIF_ALL := 0x17
 
+		if (hwnd = 0){
+			hwnd := this._hwnd
+		} else if (this._hwnd != hwnd){
+			;MsgBox % "hwnd " this._hwnd " Rejecting HWND " Format("{:x}",hwnd)
+			return
+		}
+
 		WindowRECT := this._GetClientRect()
 		this._width := WindowRECT.Right
 		this._height := WindowRECT.Bottom
@@ -549,6 +565,7 @@ Class _CGui {
 					if (max != -1){
 						value := Substr(value, 1, percent-1)
 						value := round(( max / 100 ) * value)
+						ret.flags._haspercent := 1
 					}
 				}
 			}

demo - multiple scrollbars.ahk

@@ -26,28 +26,30 @@ Class MyClass extends CWindow {
 		this.GUI_MAX_WIDTH := 500
 		this.GUI_COLUMN_2 := 300
 		this.Gui("Margin",5,5)
+
+		this.Gui("Show", "w500 h150","Scroll Demo")
 
-		this.Gui("Add", "Text", "Center xm ym w" this.GUI_MAX_WIDTH, "HWND: " this._hwnd)
+		;this.Gui("Add", "Text", "Center xm ym w" this.GUI_MAX_WIDTH, "HWND: " this._hwnd)
+		this.Gui("Add", "Text", "Center xm ym w100% ", "HWND: " this._hwnd)
 
 		this.ChildWindow1 := new CWindow(this, "-Border").GuiOption("+Parent", this)
-		this.Gui("Add", "Text", "Center xm y30 w" this.GUI_WIDTH, "HWND: " this.ChildWindow1._hwnd)
+		this.Gui("Add", "Text", "Center x0 y30 w45%", "HWND: " this.ChildWindow1._hwnd)
 		Loop 20 {
-			;this.ChildWindow1.Gui("Add", "Text", "Center xm w" this.GUI_WIDTH, "Text " A_Index)
+			;this.ChildWindow1.Gui("Add", "Text", "Center xm w50%", "Text " A_Index)
 			this.ChildWindow1.Gui("Add", "Text", "Center xm", "Text " A_Index)
 		}
-		this.ChildWindow1.Gui("Show", "x0 y50 w" this.GUI_WIDTH " h200")
-		this.ChildWindow1.AdjustToChild()
 
 		this.ChildWindow2 := new CWindow(this, "-Border").GuiOption("+Parent", this)
-		this.Gui("Add", "Text", "Center x" this.GUI_COLUMN_2 " y30 w" this.GUI_WIDTH, "HWND: " this.ChildWindow2._hwnd)
+		this.Gui("Add", "Text", "Center x50% y30 w50%", "HWND: " this.ChildWindow2._hwnd)
 		Loop 30 {
-			this.ChildWindow2.Gui("Add", "Text", "Center xm w" this.GUI_WIDTH, "Text " A_Index)
+			this.ChildWindow2.Gui("Add", "Text", "Center x0 w100%", "Text " A_Index)
 		}
-		this.ChildWindow2.Gui("Show", "x" this.GUI_COLUMN_2 " y50 w" this.GUI_WIDTH " h200")
-		this.ChildWindow2.AdjustToChild()
+		this.ChildWindow1.Gui("Show", "x0 y50 w45% h200")
+		this.ChildWindow1.AdjustToChild()
 
+		this.ChildWindow2.Gui("Show", "x55% y50 w45% h200")
+		this.ChildWindow2.AdjustToChild()
 
-		this.Gui("Show", "w500 h150","Scroll Demo")
 	}
 
 	SendMyString(){