Issue with ToDo WYSIWG area (#3374) (fixes frappe/erpnext#7773)

* fixes #7773: Issue with ToDo WYSIWG area

frappe/public/js/frappe/form/control.js

@@ -1647,6 +1647,15 @@ frappe.ui.form.ControlTextEditor = frappe.ui.form.ControlCode.extend({
 			prettifyHtml: true,
 			dialogsInBody: true,
 			callbacks: {
+				onInit: function() {
+					// firefox hack that puts the caret in the wrong position
+					// when div is empty. To fix, seed with a <br>.
+					// See https://bugzilla.mozilla.org/show_bug.cgi?id=550434
+					$(".note-editable[contenteditable='true']").on('focus', function(){
+						var $this = $(this);
+						$this.html( $this.html() + '<br>' );
+					});
+				},
 				onChange: function(value) {
 					me.parse_validate_and_set_in_model(value);
 				},