Canvas Group filled with black for mobile devices

Reproduction Steps

We have received numerous reports of this bug occuring for mobile users in our game, namely lower-end devices. This occurrence is seemingly random but consistently happens if your device suffers from the bug.

  1. I’ve only seen it happen in my game: 🕹️ nico's nextbots [ARCADE] - Roblox

  2. Select “play”, then select “arcade”, then select “spawn”

  3. When you spawn in, part of your screen should be black.

Expected Behavior

The black part of the screen should not be there at all.

Actual Behavior

The game screen is filled with black, and you won’t be able to see anything.

The reason I suspect this is a canvas group issue is:

  1. Looking at the first screenshot above, the leaderboard at the top right (whose parent is the canvas group) seems unaffected and you are able to see through the blackness. This was not something we elaborately added and is unusual behavior for Roblox GUI’s.

  2. The canvas group has a specific aspect ratio used in a UIAspectRatioConstraint, which is why it only covers a large portion of the screen. The original background transparency of the canvas group is WHITE and never changes throughout the game, so this is not a coding error of mistakenly making the background transparency 0.

Here is a screenshot of the canvas group in studio, set to 0.5 transparency for comparison and visibility:


Replace the canvas group with a frame.

Issue Area: Mobile App
Issue Type: Display
Impact: Moderate
Frequency: Often
Date First Experienced: 2023-03-03 00:03:00 (-08:00)
Date Last Experienced: 2023-03-04 00:03:00 (-08:00)


If this occurs for lower end devices, this is likely a graphics issue because CanvasGroups are essentially throttled based on device performance and graphics. We haven’t had any update on CanvasGroups in a while so I’m not even sure if this will get a fix. My guess though.

I love your game


Thanks for the report! We’ll follow up when we have an update for you.

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