发布前托管重绘与布局封版收口

收口 Dialog/overlay 后鼠标状态同步、Tooltip 临时 coverage 与持久 coverage 拆分、跨 root 脏区补提交、TextBox/Button 绘制副作用修复，并补充 KEY6 回归用例和 BUG/Fix/Feature 开发记录。

Canvas.cpp

@@ -22,6 +22,12 @@ static const char* SxCanvasMsgName(UINT m)
 
 namespace
 {
+	enum class SxCanvasOverlayRedrawMode
+	{
+		None,
+		RefreshSnapshot
+	};
+
 	bool SxCanvasRectValid(const RECT& rc)
 	{
 		return rc.right > rc.left && rc.bottom > rc.top;
@@ -209,9 +215,18 @@ bool Canvas::handleEvent(const ExMessage& msg)
 					consumed = true;
 				}
 			}
-			else if (c->clearTransientMouseState())
+			else
 			{
-				anyVisualChanged = true;
+				// 后续兄弟只走临时状态清理，不会再进入自己的 handleEvent()。
+				// Tooltip 隐藏会先回贴旧快照，再改变 coverage；因此必须先保存旧覆盖范围，
+				// 避免登记重绘时丢失旧 Tooltip 区域，导致上层 overlay 补画判断不完整。
+				const RECT previousCoverage = c->getManagedRepaintCoverageRect();
+				if (c->clearTransientMouseState())
+				{
+					if (Window* host = getHostWindow())
+						host->requestManagedRepaint(c, previousCoverage);
+					anyVisualChanged = true;
+				}
 			}
 		}
 	}
@@ -403,9 +418,11 @@ void Canvas::requestRepaint(Control* parent)
 
 		SX_LOG_TRACE("Dirty") << SX_T("Canvas 请求局部重绘：id=", "Canvas::requestRepaint(partial): id=") << id;
 
-		RECT coverage{};
-		bool hasCoverage = false;
-		auto commitManagedChild = [&](Control* child, bool forceOverlayRedraw)
+		RECT paintCoverage{};
+		bool hasPaintCoverage = false;
+		RECT persistentCoverage{};
+		bool hasPersistentCoverage = false;
+		auto commitManagedChild = [&](Control* child, SxCanvasOverlayRedrawMode overlayMode)
 			{
 				if (!child || !child->IsVisible())
 					return;
@@ -413,10 +430,10 @@ void Canvas::requestRepaint(Control* parent)
 				const bool directDirty = child->isDirty();
 				const bool subtreeDirty = child->hasManagedDirtySubtree();
 
-				if (forceOverlayRedraw)
+				if (overlayMode == SxCanvasOverlayRedrawMode::RefreshSnapshot)
 				{
 					// overlay 补画必须先作废旧快照：
-					// 下层兄弟刚刚已经写过像素，若继续沿用旧快照，会把旧背景再贴回来。
+					// 下层兄弟的持久内容刚刚已经写过像素，若继续沿用旧快照，会把旧背景再贴回来。
 					child->invalidateBackgroundSnapshot();
 					child->setDirty(true);
 					child->draw();
@@ -437,15 +454,26 @@ void Canvas::requestRepaint(Control* parent)
 					return;
 				}
 
-				const RECT childRect = child->getManagedRepaintCoverageRect();
-				if (!hasCoverage)
+				const RECT childPaintRect = child->getManagedRepaintCoverageRect();
+				if (!hasPaintCoverage)
 				{
-					coverage = childRect;
-					hasCoverage = true;
+					paintCoverage = childPaintRect;
+					hasPaintCoverage = true;
 				}
 				else
 				{
-					coverage = SxCanvasUnionRect(coverage, childRect);
+					paintCoverage = SxCanvasUnionRect(paintCoverage, childPaintRect);
+				}
+
+				const RECT childPersistentRect = child->getManagedRepaintPersistentCoverageRect();
+				if (!hasPersistentCoverage)
+				{
+					persistentCoverage = childPersistentRect;
+					hasPersistentCoverage = true;
+				}
+				else
+				{
+					persistentCoverage = SxCanvasUnionRect(persistentCoverage, childPersistentRect);
 				}
 			};
 
@@ -457,12 +485,17 @@ void Canvas::requestRepaint(Control* parent)
 
 			if (child->hasManagedDirtySubtree())
 			{
-				commitManagedChild(child, false);
+				commitManagedChild(child, SxCanvasOverlayRedrawMode::None);
 			}
-			else if (hasCoverage && SxCanvasRectsIntersect(child->getManagedRepaintCoverageRect(), coverage))
+			else if (hasPaintCoverage && SxCanvasRectsIntersect(child->getManagedRepaintCoverageRect(), paintCoverage))
 			{
 				// 位于本次累计 coverage 上方、且发生相交的兄弟控件，需要补画回最上层。
-				commitManagedChild(child, true);
+				// 但只有下层“持久内容”影响到它时，才允许作废并重新抓背景快照；
+				// 如果只是被 Tooltip 等临时浮层覆盖，则跳过兄弟补画，避免透明控件回贴旧快照擦掉 Tooltip。
+				const bool persistentHit = hasPersistentCoverage &&
+					SxCanvasRectsIntersect(child->getManagedRepaintPersistentCoverageRect(), persistentCoverage);
+				if (persistentHit)
+					commitManagedChild(child, SxCanvasOverlayRedrawMode::RefreshSnapshot);
 			}
 		}
 
@@ -502,6 +535,20 @@ RECT Canvas::getManagedRepaintCoverageRect() const
 	return coverage;
 }
 
+RECT Canvas::getManagedRepaintPersistentCoverageRect() const
+{
+	// 持久 coverage 只描述会进入背景快照语义的范围。
+	// 子控件 Tooltip 等临时浮层不会被并入，避免兄弟控件补画时抓到临时像素。
+	RECT coverage = getBoundsRect();
+	for (const auto& child : controls)
+	{
+		if (!child->IsVisible())
+			continue;
+		coverage = SxCanvasUnionRect(coverage, child->getManagedRepaintPersistentCoverageRect());
+	}
+	return coverage;
+}
+
 bool Canvas::canCommitManagedPartialRepaint() const
 {
 	// Canvas 只有在“自己本体不脏 + 仍持有有效背景快照”时，