Juce Linux DragAndDrop repaint issue

Hello,

I have found that Juce Linux also needs to force repaint it’s DragAndDrop container when dragging from a DragAndDropContainer source.

I have submitted a small PR for this issue: Force repaint for Juce Linux as well when dragging starts by alcomposer · Pull Request #1240 · juce-framework/JUCE · GitHub
As a first time contributor, is there anything else I need to do?