[Ask] The icon not same?

[DhannyNara]

• Can you tell me why the icon is not same?
  the blue and red.
  

[Infocatcher]

Icon for Private Tab button was added before Firefox 29 (with Australis and that customizable menu).

Style for userChrome.css/Stylish to use icon from "Private Window" button:

/* AGENT_SHEET */ /* <- header for Stylish */
#privateTab-toolbar-openNewPrivateTab[cui-areatype="menu-panel"] {
	list-style-image: url("chrome://browser/skin/menuPanel.svg") !important;
	-moz-image-region: rect(0, 576px, 32px, 544px) !important;
}

Or just apply grayscale filter:

#privateTab-toolbar-openNewPrivateTab[cui-areatype="menu-panel"] {
	filter: grayscale(1);
}

[DhannyNara]

may I change the icon now?