How are debugging symbols found?

I have a project that referenced an external DLL without the PDB file (let's call it version 1). I created version 2 of the DLL with the PDB file. I was able to debug, etc. no problem. Due to some variations in the code开发者_如何学运维, I deleted the PDB and went back to version 1. The /bin directory no longer has the PDB after I build but somehow, Visual Studio is still finding the source code and I can debug.

In Tools > Options > Debugging > Symbols, there are no locations. General has "Enable Just My Code" checked (I had previously unchecked it). Can someone shed some light?

Edit: I deleted the solution, tried opening it in Visual Studio (clicked OK to remove from recently used list), got the solution from source control again. The debugging info wasn't loaded again. Does VS automatically look through recent projects or something?

Debug + Other Windows + Modules. Find your DLL in the list and right-click it. The Symbol Load Information menu item tells you where it looked for the .pdb file and which one it actually used.