I've a lot of duplicated events and memory leaks with tabs widget.

An endless growing list of events like: "remove" on the tabs container "focusin", "mousedown" and "remove" on the tabs list ...

Some undesirable object references in "bindings", "classesElementLookup" ... which keep alive objects after a remove (memory leaks)

for example: in "tabs.js / function _processTabs", you setup tracked classes like this:

this._addClass( this.anchors, "ui-tabs-anchor" );

but, after in the function "_setupEvents", you get rid of all events with this :

this._off( this.anchors.add( this.tabs ).add( this.panels ) );

but in this case, the function "_untrackClassesElement" will never be triggered ... and "classesElementLookup" will keep the anchor reference forever

another thing found in the source (small mistake, no consequence but dead code):

file widget.js / function _on :

if ( selector ) {
	delegateElement.on( eventName, selector, handlerProxy );
} else {
	element.on( eventName, handlerProxy );
}

selector is a string, so the if statement will be ever true should be

if (selector.length)

Google Chrome's Accessibility Developer Tools indicates that the Accordion widget's use of a gray background fails their audit rule AX_COLOR_01:

"Text elements should have a reasonable contrast ratio" ​ ​https://github.com/GoogleChrome/accessibility-developer-tools/wiki/Audit-Rules#ax_color_01

Google Chrome's Accessibility Developer Tools indicates that the Accordion widget's use of disclosure triangles fails their audit rule AX_IMAGE_01:

"Meaningful images should not be used in element backgrounds" ​https://github.com/GoogleChrome/accessibility-developer-tools/wiki/Audit-Rules#ax_image_01