From Documentation
First, each element must be closed. They are two ways to close an element as depicted below. They are equivalent.
| | |
|---|---|
| Close by an end tag: | <window></window> |
| Close without an end tag: | <window/> |
Second, elements must be properly nested.
| | |
|---|---|
| Correct: | <window> <groupbox> Hello World! </groupbox> </window> |
| Wrong: | <window> <groupbox> Hello World! </window> </groupbox> |
XML treats every tag as a node in a tree. A node without a parent node is a root component, and it is the root of a tree. In each zul file, only ONE tree is allowed.
For example, for being a whole zul file, the following is allowed, for it has only one root component.
<button/>
And for being a whole zul file, the following is not allowed, for it has more than one root component.
<button/> <button/>
You can solve the problem by simply adding a tag enclosing the whole zul file to serve as the parent node, so the zul file has one single tree again.
<window> <button /> <button /> </window>