How to reproduce:
1. Open the attached Project (tiletest.zip)
2. Open the "TestScene" Scene
3. Select a Tile in the Tile Palette Window
4. Select the Tile Brush Tool in the Tile Palette Window
5. Attempt to paint with the Tile Brush in one of the Scene Windows by dragging
6. Notice how the Tiles appearing are completely misplaced

Expected result: Dragging the Tile Brush tool creates Tiles where you drag it
Actual result: Dragging the Tile Brush creates a line of Tiles in an incorrect position

Reproducible with: 2018.3.0b4, 2018.3.0b7, 2019.1.0a6
Not reproducible with: 2017.4.0f1, 2017.4.14f1, 2018.1.9f2, 2018.2.14f1, 2018.3.0b3

Notes: Removing the second Scene View Window seems to fix this issue. It does not matter which Scene View Window the Tiles are painted onto.