First off all, I noticed that you are using the Classic Warcraft 3 and not Reforged (as seen in the picture).
There's really no way to change the tooltip as it was already programmed by Blizzard. It's a unique thing that was introduced in 1.28.4 (I think), when both Reign of Chaos and The Frozen Throne are merged into a completely new executable file. As such, the old "Frozen Throne.exe" doesn't work anymore.
This means if you want to start ROC, you'll have to access it in-game itself by clicking on a small icon (which, in this case, the Orc warrior one) after starting "Warcraft III.exe". If you want to switch back to Expansion, click on the same icon again (it became Arthas).
If your game is updated to Reforged, then you can access the ROC campaigns. Unfortunately, you must complete all ROC campaigns (Prologue one is not necessary) in the chronological order if you want to play TFT ones, including the Founding of Durotar.