chore: fix panel double mounting (#310)

* chore: fix panel double mounting

* changeset

* ci: apply automated fixes

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

Author: AlemTuzlak

.changeset/rare-rats-tease.md

@@ -0,0 +1,5 @@
+---
+'@tanstack/devtools-utils': patch
+---
+
+fix double mounting of panels

packages/devtools-utils/src/preact/panel.tsx

@@ -34,6 +34,7 @@ export function createPreactPanel<
     const devToolRef = useRef<HTMLDivElement>(null)
     const devtools = useRef<TCoreDevtoolsClass | null>(null)
     useEffect(() => {
+      if (devtools.current) return
       devtools.current = new CoreClass()
 
       if (devToolRef.current) {

packages/devtools-utils/src/react/panel.tsx

@@ -32,6 +32,7 @@ export function createReactPanel<
     const devToolRef = useRef<HTMLDivElement>(null)
     const devtools = useRef<TCoreDevtoolsClass | null>(null)
     useEffect(() => {
+      if (devtools.current) return
       devtools.current = new CoreClass()
 
       if (devToolRef.current) {