The trendy mold of a button provides a better and consistent look for, especially, Internet Explorer 6. Unfortunately, the browser (particularly, Internet Explorer) will be slowed down if there are a lot of button (with trendy) in the same page.
Notice that the default mold is os in ZK 5, while trendy in ZK 3.6. Since ZK 7.0.0, 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>