Items missing from dock after rebooting


I'm using a G5 ppc with OS 10.5.8. Recently when I booted up my Mac & many items were missing from my dock. I corrected the problem
except for one item. This item produced a menu list in which you could pick any one of these items: Recent Applications, Recent Documents,
Recent Servers, Favorite Volumes, & Favorite Items. It's been so long since I added it to the dock, that I don't remember how to put it back into the dock. If someone knows what this is, I'm going to write it down for future reference.

I went to my backup drive to try and see what it is. It's there on my backup, but when I hold the mouse on the icon, it does not have a "Show in Finder" like all the other items in the dock.
I am assuming that the item you are looking for is a folder or a document (assuming can be dangerous). If you did a search for the item name, at the bottom of your search window should show the path to that item.
Thanks for the reply. Unfortunately, it's not a folder. This item produces a list from which to choose 5 categories: Recent Applications, Recent Documents, etc. When you click & hold the mouse over the dock icon it shows the 5 choses, then you pick the one you want. For example, if I want to see "Recent Applications" I click on that category. Then it will always show "Recent Applications" in a grid until I click onto a different category. I fact, if I did not want to keep switching back and forth between the categories, I could put this item into the dock 5 times & have 5 icons to represent each category. (I hope this better describes what this software can do. And if my memory serves me right, I believe it may have been an extra accessory that came with some other software.)
You are just clicking and holding. Have you tried holding down the control key and then click and hold? The control key gives you more options.

It would be helpful to know the name of the item. Then we can connect it to an app and be able to give help.
Yes, I'm just clicking & holding. I've never tried holding down the control key and then clicking & holding. That my big problem, It's been ages since I set this up that I don't remember what software folder it came from. Is there a plist just for the items that are in the dock? If there is, I could get that data from my backup drive & drag and drop it into the preference folder on my main drive. I was just thinking, maybe if I booted from the backup drive and held down the control key & then click & hold to show more options on that item then maybe it will have a "Show in Finder".
Well I rebooted from my backup drive to try an experiment. After the dock loaded, I held down the control key & then clicked held the mouse to see if any options were available hopefully there might be a "Show in Finder" so I could find the location of that item. But it did not show any options.
Well I finally found the solution to my problem! The application to add back my missing items was Mac Pilot/ Dock Settings/Add recent items stack on right/ click on Add Stack button. This gave the ability to make whatever list I wanted via the 5 choices (Recent Applications, Recent Documents, Recent Servers, Favorite Volumes & Favorite Items). Then to add another stack I just click on the button again. Now I have my missing items from my dock, Recent Applications & Recent Documents. I hope this will help any one else who ever has this problem. I'm writing it down for future reference.