diff --git a/packages/dashboard/app/components/Header.tsx b/packages/dashboard/app/components/Header.tsx
index 11ac2f5fd1..a649aff430 100644
--- a/packages/dashboard/app/components/Header.tsx
+++ b/packages/dashboard/app/components/Header.tsx
@@ -836,12 +836,14 @@ export function Header({
         )}
 
         {/* Project Selector - Back button when project selected, dropdown when 2+ projects (tablet + desktop) */}
-        {!isMobile && projects.length >= 1 && onViewAllProjects && onSelectProject && (
+        {!isMobile && projects.length >= 1 && onViewAllProjects && (
           <StandaloneProjectSelector
             projects={projects}
             currentProject={currentProject ?? null}
             onViewAll={onViewAllProjects}
             onSelect={onSelectProject}
+            allowSingleProject
+            viewAllLabel={t("header.manageProjects", "Manage Projects")}
           />
         )}
 
diff --git a/packages/dashboard/app/components/MailboxModal.css b/packages/dashboard/app/components/MailboxModal.css
index 1ad97c198f..4d62583b31 100644
--- a/packages/dashboard/app/components/MailboxModal.css
+++ b/packages/dashboard/app/components/MailboxModal.css
@@ -673,7 +673,7 @@
   width: var(--space-sm);
   flex-shrink: 0;
   cursor: col-resize;
-  background: transparent;
+  background: color-mix(in srgb, var(--border) 70%, transparent);
   touch-action: none;
   transition: background var(--transition-fast);
 }
diff --git a/packages/dashboard/app/components/ProjectSelector.tsx b/packages/dashboard/app/components/ProjectSelector.tsx
index 576ed9eae8..c7ca51ac00 100644
--- a/packages/dashboard/app/components/ProjectSelector.tsx
+++ b/packages/dashboard/app/components/ProjectSelector.tsx
@@ -23,6 +23,8 @@ export interface ProjectSelectorProps {
   onSelect?: (project: ProjectInfo) => void;
   onViewAll: () => void;
   recentProjectIds?: string[];
+  allowSingleProject?: boolean;
+  viewAllLabel?: string;
 }
 
 /**
@@ -77,6 +79,8 @@ export function ProjectSelector({
   onSelect,
   onViewAll,
   recentProjectIds = [],
+  allowSingleProject = false,
+  viewAllLabel,
 }: ProjectSelectorProps) {
   const { t } = useTranslation("app");
   const [isOpen, setIsOpen] = useState(false);
@@ -369,8 +373,9 @@ export function ProjectSelector({
     );
   };
 
-  // Don't render if only one project (single-project mode)
-  if (projects.length <= 1) {
+  // Standalone project switching stays hidden in single/no-project contexts unless
+  // a host uses the trigger as an explicit Manage Projects affordance.
+  if (!allowSingleProject && projects.length <= 1) {
     return null;
   }
 
@@ -384,11 +389,12 @@ export function ProjectSelector({
         aria-expanded={isOpen}
         aria-haspopup="listbox"
         aria-label={t("projectSelector.ariaLabel", "Select project")}
+        title={currentProject?.name ? t("projectSelector.switchProjectTitle", "Switch project (current: {{name}})", { name: currentProject.name }) : t("projectSelector.projectsTitle", "Projects")}
         data-testid="project-selector-trigger"
       >
         <Folder size={16} className="project-selector__trigger-icon" />
         <span className="project-selector__trigger-text">
-          {currentProject?.name || t("projectSelector.selectProject", "Select Project")}
+          {currentProject?.name || t("projectSelector.projects", "Projects")}
         </span>
         <ChevronDown
           size={14}
@@ -583,9 +589,10 @@ export function ProjectSelector({
                 highlightedIndex === totalItems - 1 ? "highlighted" : ""
               }`}
               onClick={handleViewAll}
+              data-testid="manage-projects-action"
             >
               <Grid3X3 size={14} />
-              <span>{t("projectSelector.viewAll", "View All Projects")}</span>
+              <span>{viewAllLabel ?? t("projectSelector.viewAll", "View All Projects")}</span>
             </button>
           </div>
         </div>
diff --git a/packages/dashboard/app/components/WorkflowNodeEditor.css b/packages/dashboard/app/components/WorkflowNodeEditor.css
index cc91760be7..a85274c4c8 100644
--- a/packages/dashboard/app/components/WorkflowNodeEditor.css
+++ b/packages/dashboard/app/components/WorkflowNodeEditor.css
@@ -73,6 +73,7 @@
 .wf-editor-body {
   display: flex;
   flex: 1;
+  min-width: 0;
   min-height: 0;
 }
 
@@ -537,7 +538,10 @@
 
 .wf-editor-canvas {
   flex: 1;
+  width: 100%;
+  min-width: 0;
   min-height: 0;
+  overflow: hidden;
   position: relative;
 }
 
@@ -1230,6 +1234,9 @@
 
   .wf-editor-body {
     flex-direction: column;
+    width: 100%;
+    min-width: 0;
+    overflow-x: hidden;
   }
 
   .wf-editor-body--list-stage .wf-editor-sidebar {
@@ -1254,7 +1261,10 @@
   .wf-editor-body--editor-stage .wf-editor-canvas-wrap {
     display: flex;
     flex: 1 1 auto;
+    width: 100%;
+    min-width: 0;
     min-height: 0;
+    overflow: hidden;
   }
 
   .wf-editor-body--editor-stage .wf-editor-canvas {
@@ -1305,9 +1315,27 @@
 
   .wf-editor-canvas-wrap {
     flex: 1 1 auto;
+    width: 100%;
+    min-width: 0;
     min-height: 0;
   }
 
+  .wf-editor-canvas {
+    width: 100%;
+    min-width: 0;
+    max-width: 100%;
+    overflow: hidden;
+  }
+
+  .wf-editor-canvas .react-flow,
+  .wf-editor-canvas .react-flow__renderer,
+  .wf-editor-canvas .react-flow__pane,
+  .wf-editor-canvas .react-flow__viewport {
+    width: 100%;
+    min-width: 0;
+    max-width: 100%;
+  }
+
   .wf-editor-list-item,
   .wf-editor-new,
   .wf-editor-import,
diff --git a/packages/dashboard/app/components/__tests__/WorkflowNodeEditor.css.test.ts b/packages/dashboard/app/components/__tests__/WorkflowNodeEditor.css.test.ts
index a2f9e88cd0..790ccda070 100644
--- a/packages/dashboard/app/components/__tests__/WorkflowNodeEditor.css.test.ts
+++ b/packages/dashboard/app/components/__tests__/WorkflowNodeEditor.css.test.ts
@@ -103,6 +103,72 @@ describe("WorkflowNodeEditor mobile CSS contract", () => {
     expect(collapsedToggleRule).toMatch(/bottom\s*:\s*var\(--space-sm\)\s*;/);
   });
 
+  it("FN-6034 keeps the desktop graph canvas shrinkable without removing the modal minimum", () => {
+    const baseCss = loadAllAppCssBaseOnly();
+
+    const desktopModalRule = findRule([baseCss], /\.wf-editor-modal\s*\{[^}]*\}/);
+    expect(desktopModalRule).toMatch(/min-width\s*:\s*640px\s*;/);
+
+    const bodyRule = findRule([baseCss], /\.wf-editor-body\s*\{[^}]*\}/);
+    expect(bodyRule).toMatch(/min-width\s*:\s*0\s*;/);
+
+    const canvasWrapRule = findRule([baseCss], /\.wf-editor-canvas-wrap\s*\{[^}]*\}/);
+    expect(canvasWrapRule).toMatch(/min-width\s*:\s*0\s*;/);
+
+    const canvasRule = findRule([baseCss], /\.wf-editor-canvas\s*\{[^}]*\}/);
+    expect(canvasRule).toMatch(/min-width\s*:\s*0\s*;/);
+    expect(canvasRule).toMatch(/width\s*:\s*100%\s*;/);
+    expect(canvasRule).toMatch(/overflow\s*:\s*hidden\s*;/);
+  });
+
+  it("FN-6034 makes the mobile React Flow surface fill the editor stage without horizontal overflow", () => {
+    const editorCss = readComponentCss("WorkflowNodeEditor.css");
+    const mobileBlocks = extractMediaBlocks(editorCss, "(max-width: 768px)");
+
+    const editorBodyRule = findRule(mobileBlocks, /\.wf-editor-body\s*\{[^}]*\}/);
+    expect(editorBodyRule).toMatch(/width\s*:\s*100%\s*;/);
+    expect(editorBodyRule).toMatch(/min-width\s*:\s*0\s*;/);
+    expect(editorBodyRule).toMatch(/overflow-x\s*:\s*hidden\s*;/);
+
+    const editorStageWrapRule = findRule(mobileBlocks, /\.wf-editor-body--editor-stage \.wf-editor-canvas-wrap\s*\{[^}]*\}/);
+    expect(editorStageWrapRule).toMatch(/width\s*:\s*100%\s*;/);
+    expect(editorStageWrapRule).toMatch(/min-width\s*:\s*0\s*;/);
+    expect(editorStageWrapRule).toMatch(/overflow\s*:\s*hidden\s*;/);
+
+    const canvasRule = findRule(mobileBlocks, /\.wf-editor-canvas\s*\{[^}]*\}/);
+    expect(canvasRule).toMatch(/width\s*:\s*100%\s*;/);
+    expect(canvasRule).toMatch(/min-width\s*:\s*0\s*;/);
+    expect(canvasRule).toMatch(/max-width\s*:\s*100%\s*;/);
+    expect(canvasRule).toMatch(/overflow\s*:\s*hidden\s*;/);
+
+    const reactFlowSurfaceRule = findRule(
+      mobileBlocks,
+      /\.wf-editor-canvas \.react-flow,\s*\.wf-editor-canvas \.react-flow__renderer,\s*\.wf-editor-canvas \.react-flow__pane,\s*\.wf-editor-canvas \.react-flow__viewport\s*\{[^}]*\}/,
+    );
+    expect(reactFlowSurfaceRule).toMatch(/width\s*:\s*100%\s*;/);
+    expect(reactFlowSurfaceRule).toMatch(/min-width\s*:\s*0\s*;/);
+    expect(reactFlowSurfaceRule).toMatch(/max-width\s*:\s*100%\s*;/);
+  });
+
+  it("FN-6034 preserves mobile staged editor visibility and inspector stacking", () => {
+    const editorCss = readComponentCss("WorkflowNodeEditor.css");
+    const mobileBlocks = extractMediaBlocks(editorCss, "(max-width: 768px)");
+
+    const listStageHiddenRule = findRule(
+      mobileBlocks,
+      /\.wf-editor-body--list-stage \.wf-editor-canvas-wrap,\s*\.wf-editor-body--list-stage \.wf-editor-inspector\s*\{[^}]*\}/,
+    );
+    expect(listStageHiddenRule).toMatch(/display\s*:\s*none\s*;/);
+
+    const editorStageSidebarRule = findRule(mobileBlocks, /\.wf-editor-body--editor-stage \.wf-editor-sidebar\s*\{[^}]*\}/);
+    expect(editorStageSidebarRule).toMatch(/display\s*:\s*none\s*;/);
+
+    const inspectorRule = findRule(mobileBlocks, /\.wf-editor-body--editor-stage \.wf-editor-inspector\s*\{[^}]*\}/);
+    expect(inspectorRule).toMatch(/width\s*:\s*100%\s*;/);
+    expect(inspectorRule).toMatch(/min-width\s*:\s*0\s*;/);
+    expect(inspectorRule).toMatch(/border-top\s*:\s*1px solid var\(--border\)\s*;/);
+  });
+
   it("FN-6033 keeps workflow editor touch target increases mobile-scoped", () => {
     const baseCss = loadAllAppCssBaseOnly();
     const editorCss = readComponentCss("WorkflowNodeEditor.css");