diff --git a/doc/doxyfile.in b/doc/doxyfile.in
index 98bd2b85..104ff75b 100644
--- a/doc/doxyfile.in
+++ b/doc/doxyfile.in
@@ -1069,7 +1069,7 @@ ALPHABETICAL_INDEX     = YES
 # Minimum value: 1, maximum value: 20, default value: 5.
 # This tag requires that the tag ALPHABETICAL_INDEX is set to YES.
 
-COLS_IN_ALPHA_INDEX    = 5
+COLS_IN_ALPHA_INDEX    = 3
 
 # In case all classes in a project start with a common prefix, all classes will
 # be put under the same header in the alphabetical index. The IGNORE_PREFIX tag