I think, it would be convenient to have a toolbar button that pastes the stress (acute) sign into the message text box.
The forum users have to mark the stress in Russian words very often, but few people have keyboard layouts with the acute accent or other convenient methods to type it. So they mark the stress each in their own way (with bold, color, or underline — золото, болото, долото), while there is a standard way to mark it with an acute accent — зо́лото, боло́то, долото́.
(The Unicode codepoint is U+0301 COMBINING ACUTE ACCENT)
Is it possible to add such a button to the panel?