workaround:
[contenteditable='true']:before {
content: "\feff ";
}
The element's height is the distance from its top content edge to the first applicable of the following:
- the bottom edge of the last line box, if the box establishes a inline formatting context with one or more lines
- the bottom edge of the bottom (possibly collapsed) margin of its last in-flow child, if the child's bottom margin does not collapse with the element's bottom margin
- the bottom border edge of the last in-flow child whose top margin doesn't collapse with the element's bottom margin
- zero, otherwise
For this empty div,
1 through 3 are not applicable, since the div is empty. It has no line boxes or children. Item 4 therefore applies.
The workaround enforces at least one line box inside the div, so that it gets nonzero height.