# Unity 2D animated tiles library: IsSelected variable not working or not present within RuleTileEditor.cs

It told me to download this library in order to work the animated tiles: https://github.com/Unity-Technologies/2d-extras

After this the tutorial told me to unzip the library and place it into my assets folder. It loaded into my assets folder and then got the following error:

Assets\2d-extras-master\2d-extras-master\Editor\Tiles\RuleTile\RuleTileEditor.cs(277,26): error
CS1061: 'ReorderableList' does not contain a definition for 'IsSelected' and no accessible extension
method 'IsSelected' accepting a first argument of type 'ReorderableList' could be found (are you
missing a using directive or an assembly reference?)


Does anyone perhaps know why this error is occuring.

1. Open Unity
2. On top of Unity window, you will see your version number. Will look something like, Unity 2020.3.8f1
3. Go to: https://github.com/Unity-Technologies/2d-extras
4. On Unity 2d Extras Github, check to see if your Unity version above matches the current branch. If you're unsure, do Control + F and search the word Branches to find the branches link on Github, click this. This will take you to all the branches of 2d extras.
5. Select the branch that matches your Unity Version. Ex: If my version is 2020.3, I would select the 2020.3 branch. Click the blue link to your branch.
6. Click the green code button on top right of the branch page, download zip.
8. Open your Unity project, go to Window -> Package Manager.
9. Click the + in package manager, select Add package from disk.
10. Locate your unzipped folder for 2d extras and select the package.json inside it, click open.
You are most likely on an Unity version where their ReorderableList no longer provides the IsSelected method. Looking at the GitHub repository it seems that there are different branches for different versions of Unity. For an example the branch "2020.3" no longer seems to contain a reference to IsSelected, so you need to change to an appropriate branch of the repository that works with your version of Unity.