Drag and Drop a Text component in http://localhost:4502/editor.html/content/we-retail/us/en/men.html page.
Open the Text component dialog for the edit, Author more than one line of text in the Rich Text area of the component.
Select the Text and apply for the any one styling of Lists (Example number list or Bullet list)
Try to place the cursor in first line (Or Select the text along with first line) after applying the Style. Observe that the Lists plugin got disabled.
Note: Plugin gets disabled if on the first line selected after the styles got applied.
There is no custom code its a fresh installed AEM6.4 OOTB Text component behavior.
I see the same behavior on 6.4 OOTB. If I style multiple lines at the same time Lists icon is disabled on the first line. If I style each line one after another List icon is disabled on all lines.
Also I see same behavior with Text Component under General Component Group (not just We.Retail component group). May be a bug.