popup window is cut off and therefore unusable

The popup window that opens if you hover over a widget in the widget tree is cut off and unusable if you reach the bottom of the tree view.

Either use native pop windows that can be larger than a Flutter view, make them draggable, or at least display them above the mouse, not below the mouse.

首先复现 widget tree 底部的 hover popup，并检查 widget-tree popup 的入口点；issue 没有指定文件或测试。比较 popup 在树边界附近的行为与其在更高位置时的行为，然后定义并验证一种可用的放置或调整大小行为。

由索引模型根据 Issue 内容生成。