[BUGFIX] Only focus RTE if current focus is on body tag

Focus the RTE (or its textarea fallback) only if the current focus
is on the body tag, which is the default after loading a page.
This prevents focus stealing if the focus is e.g. on an input field
before the RTE was initialized.

Resolves: #72900
Releases: master, 7.6
Change-Id: I238cd0ce1972f41e451ace674eeff350690cb427
Reviewed-on: https://review.typo3.org/47528


Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: Frank Naegler <frank.naegler@typo3.org>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>

typo3/sysext/rtehtmlarea/Resources/Public/JavaScript/HTMLArea/Editor/Editor.js

@@ -506,6 +506,11 @@ define(['TYPO3/CMS/Rtehtmlarea/HTMLArea/UserAgent/UserAgent',
 	 * Focus on the editor
 	 */
 	Editor.prototype.focus = function () {
+		if (document.activeElement.tagName.toLowerCase() !== 'body') {
+			// Only focus the editor if the body tag is focused, which is
+			// the default after loading a page
+			return;
+		}
 		switch (this.getMode()) {
 			case 'wysiwyg':
 				this.iframe.focus();