Geany version 1.24 on Windows allowed linux-style select and middle-click to paste. This seems to have been broken with version 1.25, however even 1.31 still does this in the dialogs (eg open the search and replace > select something in the search field > middle click in the paste field). I suspect it has to do with automatically deselecting a selection on click, which should only happen with a left click. Please reenable it (or make an option to) in the main editor. As someone who moves between linux and windows all day this was an extremely helpful feature.
Thanks, and keep up the good work!