Fix tab switching not updating editor content due to model URI mismatch

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## `3.6.0`
 
+- Bugfix: Fixed switching editor tabs not updating the displayed content (the previously active buffer stayed on screen) ([#410](https://github.com/zowe/zlux-editor/pull/410))
 - Bugfix: Changed initialization of menu action and disabled functions. Now, functions are used as opposed to strings that were evaluated into functions. ([#401](https://github.com/zowe/zlux-editor/pull/401))
 - Bugfix: Hardened the language server (LSP) configuration to demand "wss://" urls rather than permitting "ws://". ([#400](https://github.com/zowe/zlux-editor/pull/400))
 - Bugfix: Fixed a JSON injection flaw in "Open in new tab" and "Copy permalink" where USS file/directory names containing `"` or `\` were concatenated directly into the launch payload string. Crafted names could override the `type`/`name`/`lines` keys and cause a different file or dataset to be opened than displayed. ([#396](https://github.com/zowe/zlux-editor/pull/396))

webClient/src/app/editor/code-editor/monaco/monaco.service.ts

@@ -749,9 +749,16 @@ export class MonacoService implements OnDestroy {
   }
 
   fileDuplicateChecker(uri: string): boolean {
+    // Normalize the incoming uri the same way models are created/looked up
+    // (via monaco.Uri.parse). Models are registered under their parsed
+    // Uri.toString(), which can differ from the raw generateUri() string;
+    // comparing the raw string here would miss an existing model and cause
+    // createModel() to throw "model already exists", leaving the editor on
+    // the previous buffer when switching tabs.
+    const normalizedUri = monaco.Uri.parse(uri).toString();
     const models = this.editorControl.editorCore.getValue().editor.getModels();
     for (const model of models) {
-      if (model.uri.toString() === uri) {
+      if (model.uri.toString() === normalizedUri) {
         return true;
       }
     }