Sorry but to add items to the menu I can not find the option to enter the product categories

1. Menu is under logo , but when you scroll down and up its fixed - http://biss.com.pl

only in mac os it become like that.. how do i want my menu display in mac os appear like in windows browser, the one i drew red rectangle around ..?

This is because your facebook widget on the side is covering the menu. When you click the menu, it opens.

you have to set the initial width value to change the breakpoint. This will allow the burger menu to be enabled sooner.

you can set the breakpoint where the burger menu appears in theme options>responsive>header under initial width option.

Please open your website in Firefox html mode (CTRL+U) and check html errors you got. Please fix them first and all should be fine.

There is no menu icon, do you mean the hamburger menu icon on mobile?

In Tablet- and Laptop-Size, the menu slips under the Logo. But i'd like to switch to the mobile-menu-button, so that the menu never appears under the logo. How can i do so? (Sorry for my bad english.

The problem is some strange icon of British flag has appeared on the right top after adding items to secondary menu.

if you see the screen shot, the menu appear like in mobile version 

But when we use a Tablet with 12 inch we see menu items and not the menu symbol.So it is not possible to tip on the submenu.

On the menu page of our website, (http://tailgatetavernnh.com/tavern-menu/ ) some of the items are bolded (second column of appetizers, soup and salads) while the rest of the menu is not.  I don't see

Here's the filter portfolio menu of artist theme :

 I want the menu icon to disappear and instead only menu items.

To remove the border line, please go to theme options>menu and select the option.

We sometimes also add the 'BUY NOW' button as the last menu item, be sure to go to apperance>menus and check there as well.

sorry but we do not understand, you have menu items but they are not visible because of the color:http://prntscr.com/ijyzo5

Is it possible to make the Action Button in the menu bar a round button? If so, can you provide the CSS for that?

sorry but we do not have such an option, you can try this css to make it in one line: #Top_bar a.responsive-menu-toggle {