Maybe you are trying to move to KDE4 and you were get used to use single click to select and double click to open…
However, the original configuration of KDE4, uses the single click to open some file, that could be nasty to people who don’t like it.
The solve is hidden but easy, open the file .kde/share/config/kdeglobals and add the next string the [KDE] section:
| SingleClick=false |
By example:
| [KDE] EffectNoTooltip=false ShowDeleteCommand=false ShowIconsOnPushButtons=true SingleClick=false |
Restart the KDE, (or dolphin if you want), and its complete… Hope it helps!.