Clipdiary stores any number of clips that you specify in the program options (up to 100 thousand clips). But note that you will need disk space to store the clipboard history.
Unfortunately, it is impossible. Clipdiary uses the emulation of pressing CTRL+V to paste data. Maybe you should try Ctrl+Shift+V?
If you have problems pasting text from Clipdiary (for example, the current clipboard content is pasted instead of the selected string), the first thing you should do is try increasing the Compatibility Delay value. Try setting it to 100 or even 150.
If the problem persists, disable the Restore Clipboard Content after pasting a Clip option.
Usually you need to quickly paste one clip and continue with your work. It is the default mode - Clipdiary is hidden right after the necessary text is pasted. But sometimes you may need to keep the clipboard history window visible on the screen till you copy several clips in a row. In this case you may disable the Hide after Copying and Pasting mode from the menu or just by pressing F2 - now the program window will stay on the screen until you manually hide it.
When the program captures a new bit of data, it is compared with the five last clips for uniqueness and if you copied the same text not long ago, Clipdiary will not add it again. This way we avoid unnecessary repetitions. But if you copied it earlier (for example, one or two hours ago), the new clip will be added to the clipboard history for you to be able to quickly access it if necessary.
Yes, you can enable this feature in File->Options->General tab