God, I shoud've had never created compact mode

src/browser/base/content/ZenWorkspaces.mjs

@@ -94,6 +94,8 @@ var ZenWorkspaces = {
     }
     json.workspaces = json.workspaces.filter(workspace => workspace.uuid !== windowID);
     await IOUtils.writeJSON(this._storeFile, json);
+    this._workspaceCache = null;
+    await this._propagateWorkspaceData();
   },
 
   async saveWorkspaces() {
@@ -126,14 +128,30 @@ var ZenWorkspaces = {
       element.className = "subviewbutton";
       element.setAttribute("tooltiptext", workspace.name);
       element.setAttribute("zen-workspace-id", workspace.uuid);
-      element.innerHTML = `
+      let childs = window.MozXULElement.parseXULToFragment(`
         <div class="zen-workspace-icon">
           ${workspace.name[0].toUpperCase()}
         </div>
         <div class="zen-workspace-name">
           ${workspace.name}
         </div>
-      `;
+        <toolbarbutton closemenu="none" class="toolbarbutton-1 zen-workspace-actions">
+          <image class="toolbarbutton-icon" id="zen-workspace-actions-menu-icon"></image>
+        </toolbarbutton>
+      `);
+      childs.querySelector(".zen-workspace-actions").addEventListener("command", (event) => {
+        event.stopPropagation();
+        let button = event.target;
+        const popup = button.ownerDocument.getElementById(
+          "zenWorkspaceActionsMenu"
+        );
+        popup.openPopup(button, "after_end", 0,
+          0,
+          true /* isContextMenu */,
+          false /* attributesOverride */,
+          event);
+      });
+      element.appendChild(childs);
       element.onclick = (async () => {
         await this.changeWorkspace(workspace)
         let panel = document.getElementById("PanelUI-zen-workspaces");
@@ -311,6 +329,23 @@ var ZenWorkspaces = {
       tab.setAttribute("zen-workspace-id", activeWorkspace.uuid);
     }
   },
+
+  // Context menu management
+
+  _contextMenuId: null,
+  updateContextMenu(event) {
+    event.preventDefault();
+    let target = event.target;
+    let workspace = target.closest("[zen-workspace-id]");
+    if (!workspace) {
+      return;
+    }
+    _contextMenuId = workspace.getAttribute("zen-workspace-id");
+  },
+
+  contextDelete() {
+    this.removeWorkspace(_contextMenuId);
+  }
 };
 
 ZenWorkspaces.init();

src/browser/base/content/zen-popupset.inc.xhtml

@@ -111,4 +111,11 @@
       </html:moz-button-group>
     </panelview>
   </panelmultiview>
-</panel>
+</panel>
+
+<menupopup id="zenWorkspaceActionsMenu"
+            onpopupshowing="ZenWorkspaces.updateContextMenu(event);"
+            onpopuphidden="ZenWorkspaces._contextMenuId = null;">
+  <menuseparator/>
+  <menuitem id="context_zenDeleteWorkspace" oncommand="ZenWorkspaces.contextDelete();" data-l10n-id="zen-workspaces-panel-context-delete"/>
+</menupopup>

src/browser/locales/en-US/browser/zen-workspaces.ftl

@@ -11,3 +11,7 @@ zen-panel-ui-workspaces-create-save =
 zen-panel-ui-workspaces-create-cancel =
   .label = Cancel
   .accesskey = C
+
+zen-workspaces-panel-context-delete = 
+    .label = Delete Workspace
+    .accesskey = D

src/browser/themes/shared/zen-browser-shared.css

@@ -472,53 +472,60 @@ panelmultiview {
 
 @media (-moz-bool-pref: "zen.view.compact") {
   #navigator-toolbox,
-  #zen-appcontent-navbar-container #PersonalToolbar {
-    position: absolute;
+  #zen-appcontent-navbar-container #nav-bar {
     z-index: 1;
-    overflow: hidden;
     opacity: 0;
+    transition: .2s;
   }
 
   #navigator-toolbox {
-    width: 1px;
+    max-width: 1px;
     min-width: 0;
-    height: 100%;
   }
 
-  #zen-appcontent-navbar-container #PersonalToolbar {
+  #zen-appcontent-navbar-container #nav-bar {
     min-height: 0;
-    height: 1px;
-    width: 100%;
-  }
-
-  #navigator-toolbox:hover,
-  #navigator-toolbox:has([open="true"]) {
-    width: unset;
-    overflow: visible;
-    opacity: 1;
-  }
-
-  #zen-appcontent-navbar-container #PersonalToolbar:hover,
-  #zen-appcontent-navbar-container #PersonalToolbar:has([open="true"]) {
-    height: unset;
-    background: var(--zen-themed-toolbar-bg) !important;
-    overflow: visible;
-    border-bottom: var(--zen-appcontent-border) !important;
-    opacity: 1;
-  }
-  
-  #navigator-toolbox:hover #titlebar,
-  #navigator-toolbox:has([open="true"]:not(tab)) #titlebar {
-    background: var(--zen-themed-toolbar-bg) !important;
-    border-right: var(--zen-appcontent-border) !important;
-    padding: 0 5px;
+    max-height: 1px;
   }
 
   #tabbrowser-tabbox #tabbrowser-tabpanels .browserSidebarContainer {
     margin: 10px !important;
     margin-right: 0 !important;
+    margin-top: 0 !important;
     width: -moz-available;
   }
+
+  :root:has(
+    :is(
+      #navigator-toolbox:hover,
+      #navigator-toolbox *[open="true"],
+      #zen-appcontent-navbar-container:hover,
+      #zen-appcontent-navbar-container *[open="true"]
+    )
+  ) {
+    & #zen-appcontent-navbar-container #nav-bar,
+    & #navigator-toolbox { 
+      max-width: unset;
+      max-height: unset;
+      overflow: visible;
+      opacity: 1;
+      background: transparent !important;
+    }
+
+    & #navigator-toolbox {
+      border-right: var(--zen-appcontent-border) !important;
+      width: unset;
+      padding: 5px;
+    }
+
+    & #zen-appcontent-navbar-container #nav-bar {
+      border-bottom: var(--zen-appcontent-border) !important;
+    }
+
+    & #tabbrowser-tabbox #tabbrowser-tabpanels .browserSidebarContainer {
+      margin-top: 10px !important;
+    }
+  }
 }
 
 :root:is([chromehidden~="location"],[chromehidden~="toolbar"]) {

src/browser/themes/shared/zen-icons/icons.css

@@ -81,7 +81,8 @@
 }
 
 #PanelUI-menu-button,
-#appMenu-more-button2 {
+#appMenu-more-button2,
+#zen-workspace-actions-menu-icon {
 	list-style-image: url("menu.svg") !important;
 }
 
@@ -668,7 +669,8 @@ menuitem[id="placesContext_deleteFolder"],
 menuitem[id="placesContext_delete"],
 menuitem[id="placesContext_delete_history"],
 menuitem[id="placesContext_deleteHost"],
-#context_zenDeleteWebPanel {
+#context_zenDeleteWebPanel,
+#context_zenDeleteWorkspace {
 	--menu-image: url("edit-delete.svg");
 }
 

src/browser/themes/shared/zen-panel-ui.css

@@ -315,6 +315,11 @@
     overflow: hidden;
     text-overflow: ellipsis;
   }
+
+  & .zen-workspace-actions {
+    margin: 0;
+    margin-left: auto !important;
+  }
 }
 
 #PanelUI-zen-workspaces-current-info toolbarbutton:first-child {