UX: Textarea size does not adjust when located in tab, which is not active

[a-r-m-i-n]

Describe the bug
Textareas in edit action usually adjust their height depending on the contents. When a textarea contains more rows than the textarea initially has, a JavaScript functions increases the height of the textarea, when the edit action is loaded.

This does not work when the textarea is located in a tab, which is not active, on load. When you then switch to the tab, the textarea remains its initial size, until you trigger the onchange event. Alternativley you can switch to the tab (which appends #tab-mytab to the URL) and refresh the page, then size adjustment works.

To Reproduce
Create a textarea field within a second tab. Add more content rows than the textarea initially has. Return to index action. Open the edit action again (so you start in the first tab). Switch to the second tab.