Can't build content pipline when using "Collection of Images"-Tileset with same image several times

[Fl0l]

In Tiled i created a tileset with "Collection of Images" and added the same image twice, but with different "Image Rect" properties:

This error is thrown, when building the content:

Processor 'TiledMapTilesetProcessor' had unexpected failure!. System.ArgumentException: An item with the same key has already been added. Key: PATH_TO_CONTENT_DIR\../Grasslands/FDR_Grasslands.png
1>   at MonoGame.Extended.Content.Pipeline.Tiled.TiledMapTilesetProcessor.Process(TiledMapTilesetContentItem contentItem, ContentProcessorContext context)
1>   at Microsoft.Xna.Framework.Content.Pipeline.ContentProcessor`2.Microsoft.Xna.Framework.Content.Pipeline.IContentProcessor.Process(Object input, ContentProcessorContext context) in /home/runner/work/MonoGame/MonoGame/MonoGame.Framework.Content.Pipeline/ContentProcessor.cs:line 60
1>   at MonoGame.Framework.Content.Pipeline.Builder.PipelineManager.ProcessContent(PipelineBuildEvent pipelineEvent) in /home/runner/work/MonoGame/MonoGame/MonoGame.Framework.Content.Pipeline/Builder/PipelineManager.cs:line 846

i'm using

MonoGame 3.8.3
MonoGame.Extended 4.1.0
MonoGame.Extended.Content.Pipeline 4.1.0

[midtst0v]

first and foremost, I'd recommend reading up on .NET's generic collections, which are what the error you're getting essentially revolves around. as for the problem at hand...

I'm not entirely well-read on the Extended API, but I can infer that that the Image property of the tile is used as the key for tiles in whatever collection the API is using to store them within the tileset.

these keys are used to access the tiles in that tileset. if two tiles share the same key, they can't be differentiated--hence: An item with the same key has already been added.

I'd recommend either:

• using an image atlas as opposed to a collection of images, or
• renaming one of the tiles' images so that this key collision no longer occurs