diff --git a/src/App.css b/src/App.css
index 3561b8c..ef7d4f3 100644
--- a/src/App.css
+++ b/src/App.css
@@ -16,6 +16,19 @@
   font-size: 12px;
   color: #aaa;
   user-select: none;
+  /* Lock to a single row even when the window is narrow: buttons whose
+     text would otherwise wrap (e.g. "📡 all off") would grow the
+     titlebar, shrink .pane-wrap, and reflow every xterm. nowrap stops
+     text-wrap inside buttons, flex-shrink:0 stops children from being
+     squeezed, height locks the row height, overflow:hidden clips items
+     that don't fit (widen the window to see them). */
+  white-space: nowrap;
+  height: 34px;
+  box-sizing: border-box;
+  overflow: hidden;
+}
+.titlebar > * {
+  flex-shrink: 0;
 }
 .titlebar .label {
   font-weight: 600;
diff --git a/src/lib/layout/LeafPane.css b/src/lib/layout/LeafPane.css
index eeff96a..791a1e7 100644
--- a/src/lib/layout/LeafPane.css
+++ b/src/lib/layout/LeafPane.css
@@ -58,7 +58,17 @@
   font-size: 11px;
   color: #aaa;
   user-select: none;
-  min-height: 24px;
+  height: 24px;
+  box-sizing: border-box;
+  /* Lock height: a narrow pane used to wrap toolbar items to 2+ rows,
+     which shrank the xterm beneath and reflowed the terminal. Clip
+     overflow instead of showing a scrollbar (which would itself eat
+     into the 24px and crush the buttons). */
+  white-space: nowrap;
+  overflow: hidden;
+}
+.pane-toolbar > * {
+  flex-shrink: 0;
 }
 .pane-label {
   font: inherit;