Modernize Select2 integration and fix popover page jumping

- Upgraded Select2 from bundled v3.4.4 (2013) to v4.x peer dependency
- Removed legacy Select2 v3.x bundled files from lib directory
- Updated Select2 input to use v4.x API (events, AJAX, templates)
- Fixed Bootstrap 5 popover page jumping issue with multi-timeout scroll restoration
- Added comprehensive migration documentation in README-select2-upgrade.md
- Rebuilt all distribution files with updated source code

Breaking Changes:
- Select2 now requires separate installation as peer dependency
- AJAX configuration updated for v4.x format
- Event names changed (select2:select vs select2-loaded)
- Template functions renamed (templateResult vs formatResult)

src/element/editable-element.js

@@ -75,16 +75,15 @@ Makes editable any HTML element on the page. Applied as jQuery method.
                         e.preventDefault();
                     }
                     
-                    //stop propagation not required because in document click handler it checks event target
-                    //e.stopPropagation();
+                    //stop propagation to prevent interference with other click handlers
+                    e.stopPropagation();
                     
                     if(this.options.toggle === 'mouseenter') {
                         //for hover only show container
                         this.show();
                     } else {
-                        //when toggle='click' we should not close all other containers as they will be closed automatically in document click listener
-                        var closeAll = (this.options.toggle !== 'click');
-                        this.toggle(closeAll);
+                        //always close other containers when opening a new one
+                        this.toggle(true);
                     }
                 }, this));
             } else {