Using Edge/Chrome, upon pasting underline text in the Kendo UI Editor, the content is rendered underline, but the UI doesn't highlight the button. In turn, if the user toggles the underline style for parts of the text, it doesn't work. At this point, the button is now highlighted for the part, but switching back to no underline style doesn't have any effect regarding the rendering. Removing the style for the whole line does work as expected.
The underlined text decoration should be recognized by the UI and display.
As a comparison, here is the content after paste:
<p><span style="text-decoration-line:underline;">some text with underline</span></p>
<p><span style="text-decoration:underline;">some text with underline</span></p>