dropdownbox demo improvements

[DuckTieCorpMember]

This PR Fixes DropDownBox - Single Selection demo

Angular: DropDownBox now closes when selection is changed for the first time.
Vue: TreeView displays a selected node when you open an editor for the first time.

[Copilot]

Pull request overview

This PR fixes issues in the DropDownBox Single Selection demo across multiple frameworks (Angular, Vue, React, ReactJs, jQuery). The main improvement ensures that single selection works correctly by extracting only the first selected key from the TreeView's selection array, and properly closing the dropdown when selections are made.

Key Changes:

• Modified TreeView selection handlers to extract a single value from the selected keys array instead of passing the entire array
• Moved dropdown closing logic from onItemClick handlers to syncTreeViewSelection or value change handlers
• Added defer-rendering="false" to Vue TreeView DropDownBox to ensure initial selection displays correctly
• Cleaned up Angular implementation by replacing onOptionChanged handlers with direct selection change handlers

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
jQuery/index.js	Extracts single value from selected keys array for TreeView selection
Vue/App.vue	Adds defer-rendering, changes value from array to single value, moves close logic to syncTreeViewSelection, removes onItemClick handler
ReactJs/App.js	Extracts single value from selected keys, moves close logic to syncTreeViewSelection, removes onTreeItemClick handler
React/App.tsx	Extracts single value from selected keys, moves close logic to syncTreeViewSelection, removes onTreeItemClick handler, renames handlers for clarity
Angular/app.component.ts	Extracts single value from selected keys, adds dataGrid selection handler, removes onOptionChanged handlers
Angular/app.component.html	Removes onOptionChanged handlers, replaces two-way binding with one-way binding and event handler for DataGrid