wptouch – by default – does not render the sidebar when switching to mobile mode.
it’s not even just hiding it, it’s just not outputting it.

if you use wptouch and have the shoppingcart in a/the sidebar, it will not work as you cannot add an item to the shoppingcart if there isnt one.

this really is a shortcoming of wptouch (and i had conversations with others about this) and nothing i can “fix”

(although i generally quite like what wptouch does)

in short, if you want a truly responsive website, you will need a responsive theme…

sorry, nothing i can do in that scenario

–update: a response from wptouch to a wppizza user —

WPtouch Pro does not currently include support for eCommerce websites. However, there are others who are using it in combination without issue. To try to resolve the issue, please enable “Advanced” admin mode in Core Settings > General > Admin Mode and then enable the jQuery 2.0 setting in Core Settings > General > Tools & Debug.

Also, the ‘floating’ cart on that page is added using a widget. Widget support is not included out-of-the-box, but you can try adding support for widgets in WPtouch Pro by following the instructions here – http://www.wptouch.com/support/knowledgebase/common-customizations/ under the “Add a sidebar & widgets to the footer” section.

[The knowledge base link is for licence owner only. So coping the code below]

Add a sidebar & widgets to the footer

You may add a sidebar to the mobile theme by adding the following code at the end of the root-functions.php file in your copied child theme.

add_action( 'init', 'register_widgets' ); 
function register_widgets() { 
	register_sidebar( array( 'name' => 'WPtouch Bottom', 'id' => 'wptouch-bottom-1', 'description' => 'WPtouch sidebar for the bottom of the content' ) ); 
}
add_action( 'wptouch_body_bottom', 'output_my_sidebar_at_bottom' ); 
function output_my_sidebar_at_bottom() { 
	dynamic_sidebar( 'WPtouch Bottom' ); 
}

• In single WordPress installations, the root-functions.php file will be located at /wp-content/wptouch-data/themes/YOUR_NEW_THEME/.
• In a WordPress network installation, the root-functions.php file will be located at /wp-content/wptouch-data/YOUR_SUBSITE_ID/themes/YOUR_NEW_THEME/.

Once that code is saved, you may add widgets as you normally would through the Appearance > Widgets area of the WordPress admin area. The newly added sidebar will be named “WPtouch Bottom”.

To style your sidebar and widget content, add custom CSS: Adding Custom Styling.

If you are using shortcodes in your sidebar widget(s). Please add the following to the filter below to the functions.php file of your WPtouch Pro copied theme.

add_filter('widget_text', 'do_shortcode');