diff --git a/framework/h/app.go b/framework/h/app.go
index 61a935a..2362348 100644
--- a/framework/h/app.go
+++ b/framework/h/app.go
@@ -3,9 +3,6 @@ package h
 import (
 	"context"
 	"fmt"
-	"github.com/go-chi/chi/v5"
-	"github.com/maddalax/htmgo/framework/hx"
-	"github.com/maddalax/htmgo/framework/service"
 	"log/slog"
 	"net/http"
 	"os"
@@ -13,6 +10,10 @@ import (
 	"runtime"
 	"strings"
 	"time"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/maddalax/htmgo/framework/hx"
+	"github.com/maddalax/htmgo/framework/service"
 )
 
 type RequestContext struct {
@@ -214,9 +215,8 @@ func (app *App) start() {
 
 	port := ":3000"
 	slog.Info(fmt.Sprintf("Server started at localhost%s", port))
-	err := http.ListenAndServe(port, app.Router)
 
-	if err != nil {
+	if err := http.ListenAndServe(port, app.Router); err != nil {
 		// If we are in watch mode, just try to kill any processes holding that port
 		// and try again
 		if IsDevelopment() && IsWatchMode() {
@@ -228,14 +228,16 @@ func (app *App) start() {
 				cmd := exec.Command("bash", "-c", fmt.Sprintf("kill -9 $(lsof -ti%s)", port))
 				cmd.Run()
 			}
+
 			time.Sleep(time.Millisecond * 50)
-			err = http.ListenAndServe(":3000", app.Router)
-			if err != nil {
+
+			// Try to start server again
+			if err := http.ListenAndServe(port, app.Router); err != nil {
+				slog.Error("Failed to restart server", "error", err)
 				panic(err)
 			}
-		} else {
-			panic(err)
 		}
+
 		panic(err)
 	}
 }
diff --git a/framework/h/attribute.go b/framework/h/attribute.go
index 7cf8fd0..a9a9e72 100644
--- a/framework/h/attribute.go
+++ b/framework/h/attribute.go
@@ -2,9 +2,10 @@ package h
 
 import (
 	"fmt"
+	"strings"
+
 	"github.com/maddalax/htmgo/framework/hx"
 	"github.com/maddalax/htmgo/framework/internal/datastructure"
-	"strings"
 )
 
 type AttributeMap = map[string]any
@@ -89,9 +90,7 @@ func Checked() Ren {
 }
 
 func Id(value string) Ren {
-	if strings.HasPrefix(value, "#") {
-		value = value[1:]
-	}
+	value = strings.TrimPrefix(value, "#")
 	return Attribute("id", value)
 }
 
@@ -193,6 +192,11 @@ func Class(value ...string) *AttributeR {
 	return Attribute("class", MergeClasses(value...))
 }
 
+func ClassF(format string, args ...interface{}) *AttributeR {
+	atr := fmt.Sprintf(format, args...)
+	return Attribute("class", atr)
+}
+
 func ClassX(value string, m ClassMap) Ren {
 	builder := strings.Builder{}
 	builder.WriteString(value)
diff --git a/framework/h/cache.go b/framework/h/cache.go
index 92338cb..ad9260c 100644
--- a/framework/h/cache.go
+++ b/framework/h/cache.go
@@ -277,7 +277,7 @@ func (c *CachedNode) ClearExpired() {
 	c.mutex.Lock()
 	defer c.mutex.Unlock()
 	deletedCount := 0
-	if c.isByKey == true {
+	if c.isByKey {
 		if c.byKeyCache != nil && c.byKeyExpiration != nil {
 			for key := range c.byKeyCache {
 				expir, ok := c.byKeyExpiration[key]
@@ -303,7 +303,7 @@ func (c *CachedNode) ClearExpired() {
 }
 
 func (c *CachedNode) Render(ctx *RenderContext) {
-	if c.isByKey == true {
+	if c.isByKey {
 		panic("CachedPerKey should not be rendered directly")
 	} else {
 		c.mutex.Lock()
diff --git a/framework/h/tag.go b/framework/h/tag.go
index 611fc55..5682e87 100644
--- a/framework/h/tag.go
+++ b/framework/h/tag.go
@@ -268,9 +268,7 @@ func TagF(tag string, format string, args ...interface{}) *Element {
 		case *AttributeMapOrdered:
 			children = append(children, d)
 		case *ChildList:
-			for _, child := range d.Children {
-				children = append(children, child)
-			}
+			children = append(children, d.Children...)
 		case *AttributeR:
 			children = append(children, d)
 		default: