Applying color presets and effects is done differently. Color presets usually apply to the whole videoclip and effects can apply to the whole clip of parts thereof.
If you select an item in the effect room, then please notice the (subtle) direction in the bar just above the timeline. It can say things like:
Drag the selected video effect to the effect track, or to a video clip to apply the effect on the entire clip. Or
Drag the effect to the video clip to apply it to the entire clip.
If you want to apply a color preset to only part of the clip, then the thing to do is split the clip at the points before and after the portion of the clip you want to apply the color preset at.
Also note that color presets do not (always) work on still images, color LUTs do.
I hope that this answer your question. Otherwise please show us the (odd?) behavior of PD.