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Update: now its possible to create a custom slider with a custom thumbnail, but there is a problem at the beginning of the slider the thumbnail its cut in half...

Update: Slider in material_ui is broken? it doesnt appear the line only the thumbnail Update 2: slider material works corretly in 6.1.0 

This bug still happens with totalcross v7 ## To reproduce Create a button with button.effect=null; I have attached a minimum project with the code. [EasyUI.zip](https://github.com/TotalCross/totalcross/files/5849942/EasyUI.zip)

In my android also show like that ## Device: Device: Asus ROG II OS: Android OS Version: 9 TotalCross Version: 6.1.0

I tested the package on windows and linux arm and still has the same problem