When mouse moves onto the “x” (or “>”, depending on the sidebar status) sign (it has to be center of button, i.e. the text) to toggle sidebar, user can see hover text “x” (or “chevron-right”) which is not expected - hovering text on this button is not intended. I think you might want it to be fixed in next release.
In the meantime, I welcome anyway to manually disable this text for the time being e.g. via markdown html styling. Thanks a lot.