force minimum inspector window size on window resize events

Author: rpl

chrome/content/inspector-window.xul

@@ -44,5 +44,29 @@
     <script type="application/x-javascript">
     window.gFindBar = document.getElementById("FindToolbar");
     </script>
+
+    <script type="application/x-javascript">
+    <![CDATA[
+    const MIN_WIDTH=700, MIN_HEIGHT=600;
+    let resizeTaskID;
+
+    window.addEventListener("resize", (event) => {
+      let { outerWidth, outerHeight } = window;
+
+      let newWidth = outerWidth >= MIN_WIDTH ? outerWidth : MIN_WIDTH;
+      let newHeight = outerHeight >= MIN_HEIGHT ? outerHeight : MIN_HEIGHT;
+
+      if (outerWidth < MIN_WIDTH || outerHeight < MIN_HEIGHT) {
+        event.preventDefault();
+        if (resizeTaskID) {
+          clearTimeout(resizeTaskID);
+        }
+        resizeTaskID = setTimeout(() => window.resizeTo(newWidth, newHeight), 200);
+        return false;
+      }
+    }, false)
+    ]]>
+    </script>
+
   </vbox>
 </window>