Button: use the os mold if there are a lot of buttons

The trendy mold of a button provides a better and more consistent look, especially for Internet Explorer 6. Unfortunately, the browser (particularly, Internet Explorer) will be slowed down if there are a lot of buttons (with trendy) in the same page.

Notice that the default mold is os in ZK 5, while trendy in ZK 3.6.
` There is no difference between os and trendy.`

The default mold can be changed easily. For example,

<library-property>
    <name>org.zkoss.zul.Button.mold</name>
    <value>trendy</value>
</library-property>

Refer to ZK Configuration Reference for more information.

Prolong the Period to Check Whether a File Is Modified

ZK caches the parsed result of a ZUML page and re-compiles it only if it is modified. In a production system, ZUML pages are rarely modified so you can prolong the period to check whether a page is modified by specifying file-check-period in WEB-INF/zk.xml as shown below. By default, it is 5 seconds.

<desktop-config>
    <file-check-period>600</file-check-period><!-- unit: seconds -->
</desktop-config>