Also, Just to clarify: This is a feature of the OpenXcom Extended Plus (OXCE+) build. Meridian developed it there and I'm not sure if Yankes has pulled it up into his branch (Extended).
Yes, this is OXCE+. This is X-COM Files mod, which only works with OXCE+. I asked after seeing the feature in an X-COM Files "let's play".
Verbose log won't help with this, the log is pretty sparse on player input information, even when verbose.
Can I rebuild the binary with some compilation keys to get more information? Or would I need to add extra calls to logging functions?
You obably have mouse-wheel click bound to something other than middle-click in your OS.
X Window uses it to insert from one of clipboards. Can that interfere? Any suggestions for KDE?
Also, I think this conflicts with the middle-click for map scroll option from OXC.
Closer look for clicks on enemies, dragging for clicks anywhere else. If done correctly, it should not conflict.
Update: Dragging works after I press and hold the middle button. The red box jumps to the right when I press and release it. What about the correct work: does the picture appear for press or for release?
Update 2: There doesn't seem to be any way to disable paste with X or KDE tools. I'll try to map it to another key in sources. Does anybody know the commit? Or at least how does Meridian call it?
Update 3: Was it "Alien Inventory" added in late December-early January 2016-17?
Update 4: Looks like this feature is mutually exclusive with dragging Battlescape with middle button. I enabled it by disabling the line
_info.push_back(OptionInfo("battleDragScrollButton", &battleDragScrollButton, SDL_BUTTON_MIDDLE));
in src/Engine/Options.cpp
How can I disable drag-scrolling in Battlescape?
Update 5: Setting
battleDragScrollButton: 0
in ~/.config/openxcom/options.cfg helped. I'll leave it that way for now.
I guess, the correct way would be allowing to reassign both actions from Options -> Controls. Does it allow to set mouse clicks to actions?
Update 6: drag scroll can be disabled in Battlescape section of Options.