**System Information**
Operating system: Windows 10
**Blender Version**
Broken: (example: 2.80, edbf15d3c044, master, 2018-11-28, as found on the splash screen)
gif showing the error
https://imgur.com/a/J7wiido
Quick detour beforehand: copy-paste behaviour is dependent on row/channels selection:
- if you have no row/channels selected, all copied keyframes will be pasted
- if you have only a subset of row/channels selected, only keyframes matching this selection will be pasted [afaik this is expected behavior and was also the case in 2.79]
OK, now click-drag-box-selecting does not play very nice with this:
- once started, all previously selected rows/channels will be deselected [thats pretty bad workflow-wise, box selection with B doesnt suffer from this]
- if you happen to start the drag on a particular row/channel, only that row/channel will get selected [equally bad]
original report:
When you select with the mouse, click, drag and select the keys copy and paste (having more that 2 channels with keyframes like in the gif selected) he will only select 1 channel and only pastes 1 channel and not the 3. There are other work arounds like I show in the gif so that this doesnt happen like clicking B ou selecting from down to the channels you want.