Black box appearing next to the hot-reload icon

[gogopro-dev]

Describe the bug
There is a black box following the icon

untitled.mp4

To Reproduce
Run KMP template project
https://kmp.jetbrains.com/?android=true&ios=true&iosui=compose&desktop=true&includeTests=true
Before building bump all plugin and language versions to match the environment in the issue.

Expected behavior
No black box appearing

Environment

• OS: Windows 24H2, 26100.4946
• GPU: AMD Radeon 8060s, AMD PRO drivers, ver. 25Q3
• Kotlin version: 2.2.0
• Compose Multiplatform version: 1.8.2
• Compose Hot Reload version: 1.0.0-beta05
• IDE: IntellijIDEA 2025.2
• JVM: JBR 21.0.8
• Gradle task: hotRunJvm --auto

[sellmair]

Hey, thanks for reporting!
Are you using any remote development here? E.g., connecting to the machine remotely?

[gogopro-dev]

Hi, not at all. Everything is run locally.

[AbdullinAM]

@gogopro-dev Hey! The issue is related to the transparency settings of the devtools window. Thank you for reporting, I will take a look.

As a workaround, you can disable the transparency of the devtools window using compose.reload.devToolsTransparencyEnabled property. The UI will change a little, but there will be no black box. Just add -Dcompose.reload.devToolsTransparencyEnabled=false as an argument to your gradle run task

Also, will you be able to run this code snippet and share its output? This can help us identify the root cause of the issue

fun transparencyInfo() {
    val ge = GraphicsEnvironment.getLocalGraphicsEnvironment()
    val screenDevice = ge.defaultScreenDevice
    println("PERPIXEL_TRANSPARENT=${screenDevice.isWindowTranslucencySupported(GraphicsDevice.WindowTranslucency.PERPIXEL_TRANSPARENT)}")
    println("TRANSLUCENT=${screenDevice.isWindowTranslucencySupported(GraphicsDevice.WindowTranslucency.TRANSLUCENT)}")
    println("PERPIXEL_TRANSLUCENT=${screenDevice.isWindowTranslucencySupported(GraphicsDevice.WindowTranslucency.PERPIXEL_TRANSLUCENT)}")
}

[gogopro-dev]

@AbdullinAM Hi!
I can confirm that the workaround works as expected.
The output with or without -Dcompose.reload.devToolsTransparencyEnabled=false is the same:

PERPIXEL_TRANSPARENT=true
TRANSLUCENT=true
PERPIXEL_TRANSLUCENT=true

Let me know if you need anything else from me

[AbdullinAM]

@gogopro-dev Got it, thanks! I'm glad that the workaround helped!

We're currently working on a feature that should solve this issue, so (hopefully) this will be fixed in the future releases