I put same code for Tab1 and Tab2 but components on a Tab greater one are sized wrong. Same code should bring same UI.

Example Code:

<?page title="bug_example" contentType="text/html;charset=UTF-8"?>
<zk>
<tabbox id="tabbox" width="780px">
<tabs>
<tab id="tab1" label="Tab1" />
<tab id="tab2" label="Tab2" />
</tabs>
<tabpanels>
<tabpanel id="tabA">
<groupbox width="765px" closable="false" mold="3d">
<caption id="captionA" label="Test" />

<grid width="750px" sizedByContent="true">
<rows>
<row>
<space width="90px" />
<label value="Label:" />
<textbox width="110px" readonly="true" mold="rounded" />
</row>
</rows>
</grid>
</groupbox>
</tabpanel>
<tabpanel id="tabB">
<groupbox width="765px" closable="false" mold="3d">
<caption id="captionB" label="Test" />

<grid width="750px" sizedByContent="true">
<rows>
<row>
<space width="90px" />
<label value="Label:" />
<textbox width="110px" readonly="true" mold="rounded" />
</row>
</rows>
</grid>
</groupbox>
</tabpanel>
</tabpanels>
</tabbox>
</zk>