Hello Ljubo Žižić,
You can achieve this by using the PanelBarGroupExpanding event. The event is fired when a group is expanding.
1. I have added three different groups with captions "Default Caption", "Caption" and "DefaultCaption"
2. I subscribed to PanelBarExpanding event of RadPanelBar
3. In the event handler, I canceled the expansion of a group with caption different than "Caption". "Caption" is the caption of the group which I want to disable to collapse.
void radPanelBar1_PanelBarGroupExpanding(object sender, PanelBarGroupCancelEventArgs args)
if (args.Group.Caption != "Caption")
args.Cancel = true;
In the above code I cancel the expanding of all groups with Captions different than "Caption". I hope this helps.
the Telerik team