Update click tutorial.

tutorials/Mouse_Events/README.md

@@ -14,6 +14,7 @@ so code like this will work on both platforms:
 
 ```kotlin
 import androidx.compose.desktop.Window
+import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.*
 import androidx.compose.material.Text
@@ -21,17 +22,20 @@ import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.unit.IntSize
 import androidx.compose.ui.unit.sp
 
 fun main() = Window(title = "Compose for Desktop", size = IntSize(400, 400)) {
     var count = remember { mutableStateOf(0) }
     Box(contentAlignment = Alignment.Center, modifier = Modifier.fillMaxWidth()) {
-        var text = remember { mutableStateOf("Click me!") }
+        var text = remember { mutableStateOf("Click magenta box!") }
-        Text(
+        Column {
-            text = text.value,
+            Box(
-            fontSize = 50.sp,
                 modifier = Modifier
+                    .background(Color.Magenta)
+                    .fillMaxWidth(0.7f)
+                    .fillMaxHeight(0.2f)
                     .clickable(
                         onClick = {
                             text.value = "Click! ${count.value++}"
@@ -43,8 +47,9 @@ fun main() = Window(title = "Compose for Desktop", size = IntSize(400, 400)) {
                             text.value = "Long click! ${count.value++}"
                         }
                     )
-                .align(Alignment.Center)
             )
+            Text(text = text.value, fontSize = 40.sp)
+        }
     }
 }
 ```