Tables Broken

[Tom-Finke]

The Tables in the Rich Text Editor seem to be broken. They work fine when created in Markdown.

Creating The Table works fine, but the horizontal lines are barely visible, the vertical lines not at all:

When I open the preview, the table is broken

When I add a column: The column gets added in the middle and the Header 2 moves down

When written im Markdown, the tables looks fine but is still missing vertical lines