Hi lizac,
Apologies for the very late response!
I'll first start by providing two different solutions before explaining what the problem was.
The first option is to add an onopen event handler in your tree's root (see highlighted region):
<canvas>
<bluestyle name="defaultstyle" isdefault="true"/>
<alert id="errMsg" title="Error"/>
<include href="lz/tree.lzx" />
<splash/>
<dataset name="projects" request="true" type="file"
src="file:tikalProjects.xml"
onerror="errMsg.setAttribute('text',
'dataset Error: getting data from '+this.src+' !');
errMsg.open();"
ontimeout="errMsg.setAttribute('text',
'dataset Timeout: getting data from '+this.src+' !');
errMsg.open();"
/>
<view name="main" width="300" height="300" clip="true">
<view name="contents">
<tree datapath="projects:/root" autoscroll="true" showroot="false"
text="$path{'@name'}" open="$path{'@isopen'}">
<method event="onopen" args="o">
if (typeof(o) == 'string') {
this.setAttribute('open', (o == 'true'));
}
</method>
<tree datapath="*" isleaf="$path{'@isleaf'}" text="$path{'@name'}">
<method event="onactivate">
var url = this.datapath.xpathQuery('@url');
if (url != null) {
LzBrowser.loadURL(url,'tikalMainView');
}
</method>
</tree>
</tree>
</view>
<scrollbar/>
</view>
</canvas>
Alternatively, you can go and fix basetree, located in lps/components/base/basetree.lzx. Find the _setOpen() method and, in what I believe should be line 231, replace
if (!_initcomplete && typeof(o) == "string") {with/* removed !_initcomplete */
if (typeof(o) == "string") {Since datapaths always resolve to strings, basetree has special logic to re-typecast its boolean attributes like open, selected, and isleaf. The open attribute controls the visibility of a tree's "children" view and, when it's set to a string instead of a boolean, the height of the tree doesn't get updated (i.e. it remains 0). In turn, this affects the scrollbar because it doesn't know that the content height has changed.
Let me know if this helps and thanks for your patience!
Cheers,
pablo