Support nested horizontal scrollviews?

[X-Wei]

From the doc it's stated that "the Selectable widget must be a descendant of the scrollable widget" in order to work. So I shall wrap Selectable around MarkdownBody but under a SingleChildScrollView for selectable to work (i.e. SingleChildScrollView -> Selectable -> MarkdownBody), example code.

However, if there are code blocks inside the markdown source, they are rendered as a horizontal scrollview, and selectable will not work well for that area. E.g. if I horizontally scroll then try to select, it selects the text that were in that position before the scroll happens.

Is there any workaround to make it work better for the nested srcollables?