diff --git a/docs/configuration.md b/docs/configuration.md
index a007467a..9188b0bd 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -163,7 +163,10 @@ Currently Catch enables `CATCH_CONFIG_WINDOWS_SEH` only when compiled with MSVC,
 
 `CATCH_CONFIG_POSIX_SIGNALS` is on by default, except when Catch is compiled under `Cygwin`, where it is disabled by default (but can be force-enabled by defining `CATCH_CONFIG_POSIX_SIGNALS`).
 
-`CATCH_CONFIG_WINDOWS_CRTDBG` is off by default. If enabled, Windows's CRT is used to check for memory leaks, and displays them after the tests finish running.
+`CATCH_CONFIG_WINDOWS_CRTDBG` is off by default. If enabled, Windows's
+CRT is used to check for memory leaks, and displays them after the tests
+finish running. This option only works when linking against the default
+main, and must be defined for the whole library build.
 
 `CATCH_CONFIG_WCHAR` is on by default, but can be disabled. Currently
 it is only used in support for DJGPP cross-compiler.