Where can I get dise bar get?

Try to type:
ToolbarReset
And then Restart Rhino
(PS! @stevebaer or whom it conserns: The ToolbarReset should have a warning with a cancel option in case it was started by mistake)
thank you
it works
You can also go Tools -> Toolbar Layout, click the “+” next to “Toolbars”, click on “Size and Styles”, finally make sure “Sidebar visible” is checked