Describe the bug
The blinking text cursor (caret) does not appear when the RichText is an inline element, and a non-transparent background color is set.

To Reproduce

// Cursor is hidden
<RichText
  tagName="span"
  style={{ backgroundColor: 'yellow' }}
  value="RichText span (inline)"
/>

// Cursor appears
<RichText
  tagName="span"
  style={{ backgroundColor: 'yellow', display: 'inline-block' }}
  value="RichText span (inline-block)"
/>

Expected behavior
Cursor should appear, or the limitation should be documented.

Screenshots
Chrome:

Safari:

In Safari you can see that the cursor is hidden underneath. Indeed, the cursor is visible when background-color: transparent.