fix new file path and error page

internal/handlers/editor.go

@@ -55,40 +55,62 @@ func (h *Handlers) CreateNoteHandler(c *gin.Context) {
 		return
 	}
 
+	// Normalize slashes: treat backslashes as folder separators
+	folderPath = strings.ReplaceAll(folderPath, "\\", "/")
+	title = strings.ReplaceAll(title, "\\", "/")
+
+	// Merge any subfolder segments included in title into folderPath
+	if strings.Contains(title, "/") {
+		dirPart := filepath.Dir(title)
+		base := filepath.Base(title)
+		if dirPart != "." && dirPart != "" {
+			if folderPath == "" {
+				folderPath = dirPart
+			} else {
+				folderPath = filepath.Join(folderPath, dirPart)
+			}
+		}
+		title = base
+	}
+
+	// Strip any leading separators that might imply absolute path
+	folderPath = strings.TrimPrefix(folderPath, "/")
+	title = strings.TrimPrefix(title, "/")
+
 	// Security check
 	if strings.Contains(folderPath, "..") || strings.Contains(title, "..") {
 		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid path or title"})
 		return
 	}
 
-	// Check if path is in skipped directories
+	// Check if path is in skipped directories (after merging title path)
 	if utils.IsPathInSkippedDirs(folderPath, h.config.NotesDirSkip) {
 		c.JSON(http.StatusForbidden, gin.H{"error": "Cannot create notes in this directory"})
 		return
 	}
 
-    // Determine extension logic
+	// Determine extension logic
-    ext := strings.TrimPrefix(strings.ToLower(filepath.Ext(title)), ".")
+	ext := strings.TrimPrefix(strings.ToLower(filepath.Ext(title)), ".")
-    if ext == "" {
+	if ext == "" {
-        // No extension provided: default to markdown
+		// No extension provided: default to markdown
-        title += ".md"
+		title += ".md"
-        ext = "md"
+		ext = "md"
-    } else {
+	} else {
-        // Has extension: allow if md or in allowed file extensions
+		// Has extension: allow if md or in allowed file extensions
-        allowed := ext == "md"
+		allowed := ext == "md"
-        if !allowed {
+		if !allowed {
-            for _, a := range h.config.AllowedFileExtensions {
+			for _, a := range h.config.AllowedFileExtensions {
-                if strings.EqualFold(a, ext) {
+				if strings.EqualFold(a, ext) {
-                    allowed = true
+					allowed = true
-                    break
+					break
-                }
+				}
-            }
+			}
-        }
+		}
-        if !allowed {
+		if !allowed {
-            c.JSON(http.StatusBadRequest, gin.H{"error": "File extension not allowed"})
+			c.JSON(http.StatusBadRequest, gin.H{"error": "File extension not allowed"})
-            return
+			return
-        }
+		}
-    }
+	}
 
 	// Create full path
 	var notePath string

web/templates/base.html

@@ -288,7 +288,7 @@
             </div>
 
             <!-- File Tree -->
-            <div class="sidebar-content flex-1 overflow-y-auto px-4 pb-4">
+            <div id="sidebar-tree" class="sidebar-content flex-1 overflow-y-auto px-4 pb-4">
                 {{if .notes_tree}}
                     {{/* Render only children of the root to hide root folder label */}}
                     {{range .notes_tree.Children}}
@@ -467,6 +467,69 @@
             // Expand active path in tree
             expandActivePath();
 
+            // Sidebar tree fallback: if server didn't render any tree nodes (e.g., error pages), fetch and render via API
+            (function ensureSidebarTree() {
+                const container = document.getElementById('sidebar-tree');
+                if (!container) return;
+                const hasTree = container.querySelector('.tree-node, .sidebar-item');
+                if (hasTree) return; // already populated
+
+                // Fetch tree
+                fetch('/api/tree')
+                    .then(r => r.json())
+                    .then(data => {
+                        if (!data || !Array.isArray(data.children)) return;
+                        // Clear container
+                        container.innerHTML = '';
+                        data.children.forEach(child => {
+                            container.appendChild(renderTreeNode(child));
+                        });
+                        // Re-apply expanded state and active path if any
+                        expandActivePath();
+                    })
+                    .catch(() => {/* ignore */});
+
+                function renderTreeNode(node) {
+                    const wrapper = document.createElement('div');
+                    wrapper.className = 'tree-node';
+                    if (node.children && node.children.length) {
+                        const toggle = document.createElement('div');
+                        toggle.className = 'tree-toggle flex items-center py-1 hover:bg-gray-700 rounded px-2 cursor-pointer';
+                        toggle.setAttribute('data-path', node.path || '');
+                        toggle.innerHTML = '<i class="fas fa-chevron-right transform transition-transform duration-200 mr-2 text-xs tree-chevron"></i>' +
+                                          '<span class="mr-2">📁</span>' +
+                                          `<span class="flex-1">${escapeHTML(node.name || '')}</span>`;
+                        const children = document.createElement('div');
+                        children.className = 'tree-children ml-4 hidden';
+                        (node.children || []).forEach(ch => {
+                            children.appendChild(renderTreeNode(ch));
+                        });
+                        wrapper.appendChild(toggle);
+                        wrapper.appendChild(children);
+                    } else {
+                        let href = '/view_text/' + (node.path || '');
+                        let icon = '📄';
+                        if ((node.type || '').toLowerCase() === 'md') {
+                            href = '/note/' + (node.path || '');
+                            icon = '📝';
+                        } else if ((node.type || '').toLowerCase() === 'image') {
+                            href = '/serve_attached_image/' + (node.path || '');
+                            icon = '🖼️';
+                        }
+                        const a = document.createElement('a');
+                        a.href = href;
+                        a.className = 'sidebar-item';
+                        a.innerHTML = `<span class="mr-2">${icon}</span><span>${escapeHTML(node.name || '')}</span>`;
+                        if ((node.type || '').toLowerCase() === 'image') a.target = '_blank';
+                        wrapper.appendChild(a);
+                    }
+                    return wrapper;
+                }
+                function escapeHTML(str) {
+                    return String(str).replace(/[&<>"']/g, s => ({'&':'&amp;','<':'&lt;','>':'&gt;','"':'&quot;','\'':'&#39;'}[s]));
+                }
+            })();
+
             // Search modal wiring
             const searchModal = document.getElementById('search-modal');
             const openSearchBtn = document.getElementById('open-search');