I am trying to create a tile brush and I can’t get it to work. I swear this was working before I upgraded. I’m on OS X. I select multiple tiles and hit cmd-C and it used to create a tile brush I could stamp around. Currently, it just creates a simple tile and seems to randomly stamp one of the tiles in my copy? Am I doing something wrong, or did this break?
It seems to be intermittent, or I’m unknownly in the wrong “mode” (I’m in stamp mode). Sometimes I select multiple tiles from a tileset and can stamp them down, other times it seems to only select 1 of the tiles. Quitting Tiled seems to fix it most of the time.
This sounds like you have accidentally enabled “random mode”.
It’s not so hard, because it has the somewhat hidden shortcut “D” (for “Dice” I presume) to toggle this mode on/off. You can also find it as a toggle button on the tool bar.
Quitting Tiled helps as well because the random mode is not persistent. 
Yes! You are correct. Thanks, that was driving me crazy,