From b6097bbae6bc72981ab40b1126ee79e50e039eb4 Mon Sep 17 00:00:00 2001
From: Agent Zero <agent@agent-zero.ai>
Date: Wed, 17 Jun 2026 07:42:47 +0100
Subject: [PATCH] feat(editor): add Open file button to canvas tab bar

In canvas panel mode the '+' tab button was hardcoded to create a new
Markdown file. The 'Open' option only appeared in the empty-state
screen and in the modal-mode header dropdown (via installHeaderNewMenu)
which is not mounted when the editor runs as a canvas surface.

Adds a folder_open icon button immediately before the '+' button in
the tab bar. It calls the existing runNewMenuAction('open') ->
openFileBrowser() pipeline so no logic changes are needed. Users can
now open an existing file at any time without first closing all tabs.
---
 plugins/_editor/webui/editor-panel.html | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/plugins/_editor/webui/editor-panel.html b/plugins/_editor/webui/editor-panel.html
index 310a8f7a39..050599a91c 100644
--- a/plugins/_editor/webui/editor-panel.html
+++ b/plugins/_editor/webui/editor-panel.html
@@ -38,6 +38,16 @@
                 </button>
               </div>
             </template>
+            <button
+              type="button"
+              class="editor-new-tab"
+              title="Open file"
+              aria-label="Open file"
+              :disabled="$store.editor.loading || $store.editor.saving"
+              @click="$store.editor.runNewMenuAction('open')"
+            >
+              <span class="material-symbols-outlined" aria-hidden="true">folder_open</span>
+            </button>
             <button
               type="button"
               class="editor-new-tab"