Steps to Reproduce

1. run the zul

<zk>
	<button label="submit"></button>
	<button label="submit" iconSclass="z-icon-search"></button>
</zk>

Current Result

a button with a font awesome icon is higher than a default button

Only found on Windows Chromium-based browsers. The image below was captured on macOS Chrome 85.

Expected Result

both have the same height by default.

Font awesome is a built-in icon set, users would expect it works by default without any issue. Therefore, a button with an icon should look consistent in size.

Debug Information

line-height: normal;

Depends on the user agent. Desktop browsers (including Firefox) use a default value of roughly 1.2, depending on the element's font-family.

Since the used font-family is different between macOS (Helvetica Neue) and Windows (Arial), it could be a root cause.

Workaround

.z-button i {
	font-size: 14px;
}