MaskEditor can not edit mask

### Prerequisites

- [x] I am running the latest version of ComfyUI
- [x] I have searched existing issues to make sure this isn't a duplicate
- [x] I have tested with all custom nodes disabled ([see how](https://docs.comfy.org/troubleshooting/custom-node-issues#step-1%3A-test-with-all-custom-nodes-disabled))

### What happened?

Having a "Load Image" node with a loaded image, right click, Open in MaskEditor | Image Canvas, move the mouse with the circle and then click and drag to paint a mask.

But no mask is painted, as it was in earlier versions.

Using the color chooser a mask is created and shown.

Having a color chooser generated mask and then using the mouse to paint a mask hides during the button press the already selected parts, but nothing is added during the drag and when releasing the button again only the prior existing mask (created with the color chooser) is shown again

### Steps to Reproduce

1. Using Linux (Kubuntu, latest LTS) and chrome 144.0.7559.96 (current stable), as well as 145.0.7632.5 (current beta), using a normal window, as well as a private window. Firefox is working, though.
2. doing the steps above

### How is this affecting you?

Feature doesn't work as expected

### ComfyUI Frontend Version

1.36.14

### Browser

Chrome/Chromium

### Console Errors

```javascript
Nothing:

Checkpoint files will always be loaded safely.
Total VRAM 15954 MB, total RAM 63981 MB
pytorch version: 2.8.0+cu128
xformers version: 0.0.32.post2
Set vram state to: NORMAL_VRAM
Device: cuda:0 NVIDIA GeForce RTX 4090 Laptop GPU : cudaMallocAsync
Using async weight offloading with 2 streams
Enabled pinned memory 60782.0
WARNING: You need pytorch with cu130 or higher to use optimized CUDA operations.
Found comfy_kitchen backend cuda: {'available': True, 'disabled': True, 'unavailable_reason': None, 'capabilities': ['apply_rope', 'apply_rope1', 'dequantize_nvfp4', 'dequantize_per_tensor_fp8', 'quantize_nvfp4', 'quantize_per_tensor_fp8', 'scaled_mm_nvfp4']}
Found comfy_kitchen backend triton: {'available': True, 'disabled': True, 'unavailable_reason': None, 'capabilities': ['apply_rope', 'apply_rope1', 'dequantize_nvfp4', 'dequantize_per_tensor_fp8', 'quantize_nvfp4', 'quantize_per_tensor_fp8']}
Found comfy_kitchen backend eager: {'available': True, 'disabled': False, 'unavailable_reason': None, 'capabilities': ['apply_rope', 'apply_rope1', 'dequantize_nvfp4', 'dequantize_per_tensor_fp8', 'quantize_nvfp4', 'quantize_per_tensor_fp8', 'scaled_mm_nvfp4']}
Using xformers attention
Python version: 3.12.3 (main, Jan 8 2026, 11:30:50) [GCC 13.3.0]
ComfyUI version: 0.10.0
ComfyUI frontend version: 1.36.14
[Prompt Server] web root: /home/sl/devel/StableDiffusion/ComfyUI/venv/lib/python3.12/site-packages/comfyui_frontend_package/static
/home/sl/devel/StableDiffusion/ComfyUI/venv/lib/python3.12/site-packages/kornia/feature/lightglue.py:44: FutureWarning: `torch.cuda.amp.custom_fwd(args...)` is deprecated. Please use `torch.amp.custom_fwd(args..., device_type='cuda')` instead.
@torch.cuda.amp.custom_fwd(cast_inputs=torch.float32)
Skipping loading of custom nodes
Context impl SQLiteImpl.
Will assume non-transactional DDL.
Assets scan(roots=['models']) completed in 0.030s (created=0, skipped_existing=701, total_seen=701)
Starting server

To see the GUI go to: http://127.0.0.1:8188
```

### Logs

```shell

```

### Additional Context

_No response_

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-8249-MaskEditor-can-not-edit-mask-2f06d73d365081ad8d25eda134c6039d) by [Unito](https://www.unito.io)