Hello, Eric,
You should have a look to the Config.xml file of your N++ configuration :
Depending on your initial N++ installation ( With the installer OR from a ZIP or 7Z archive ), it may be located :
In the same folder as Notepad++ .exe, in case of local installation
In case of classic installation, with the installer, you probably find it :
In %AppData%\Roaming\Notepad++, for a W7, W8 or W10 configuration
In %AppData%\Notepad++, for a XP or Vista configuration
Then :
Close any instance of Notepad++
Open your Config.xml file, with an OTHER editor than N++
Near the end of this file, you’ll notice the <FindHistory> section
As for me, presently, it contains the following lines :
<!-- The History of opened files list -->
<FindHistory nbMaxFindHistoryPath="10" nbMaxFindHistoryFilter="10" nbMaxFindHistoryFind="10" nbMaxFindHistoryReplace="10" matchWord="no" matchCase="yes" wrap="no" directionDown="yes" fifRecuisive="yes" fifInHiddenFolder="no" dlgAlwaysVisible="no" fifFilterFollowsDoc="no" fifFolderFollowsDoc="no" searchMode="2" transparencyMode="1" transparency="128" dotMatchesNewline="yes">
    <Path name="C:\_692" />
    <Filter name="*.txt" />
    <Find name="(?-s)^(.*?,){15}\h*\K[^,\r\n]+" />
    <Find name="(?-s)^(.*?,){15}\h*\K[^,]+" />
    <Find name="(?-s)^(.*?,){13}\h*\K[^,]+" />
    <Find name="(?-s)^(.*?,){13}\h*\K[^,\r\n]+" />
    <Find name="(?-s)^(.*?,){0}\h*\K[^,\r\n]+" />
    <Find name="(?-s)^(.*?,){3}\h*\K[^,\r\n]+" />
    <Find name="(?-s)^(.*?,){12}\h*\K[^,\r\n]+" />
    <Find name="(?-s)^(.*?,){6}\h*\K[^,\r\n]+" />
    <Find name="(?-s)^(.*?,){4}\h*\K[^,\r\n]+" />
    <Find name="(?-s)^(.*?,){4}\h*\K[^\h,\r\n]+" />
    <Replace name="(?1:#\r\n)" />
    <Replace name="(?1:#)" />
    <Replace name="1234" />
    <Replace name="   \1  |" />
    <Replace name="   \d  |" />
    <Replace name=" \1" />
    <Replace name="  \1" />
    <Replace name="                              " />
    <Replace name="          " />
    <Replace name="\t\t\t" />
</FindHistory>
Finally, change the number 
10 in the 
first line, after the comment, for the 
nbMaxFindHistoryFind value :-))
I’ve never tested, with other number than 10, myself, but this should work, anyway !
Best Regards,
guy038