diff --git a/winaccessibility/inc/ResIDGenerator.hxx b/winaccessibility/inc/ResIDGenerator.hxx
index 19e06c9b88ad..400f58a2e620 100644
--- a/winaccessibility/inc/ResIDGenerator.hxx
+++ b/winaccessibility/inc/ResIDGenerator.hxx
@@ -19,20 +19,22 @@
 
 #pragma once
 
-#define PRIMARY_RESID 0x00000001
 #include <deque>
 
 //ResID i.e. MSAA child ID,
 //this class is responsible for generating a child ID
+//
+// In IAccessible2, negative child IDs are commonly used to
+// indicate unique resource IDs.
 class ResIDGenerator
 {
 private:
-    long max;
+    long m_nMin;
     std::deque<long> subList;
 
 public:
-    ResIDGenerator(long maxNum = PRIMARY_RESID)
-        : max(maxNum)
+    ResIDGenerator()
+        : m_nMin(-1)
     {
     }
     ~ResIDGenerator();
diff --git a/winaccessibility/source/service/ResIDGenerator.cxx b/winaccessibility/source/service/ResIDGenerator.cxx
index 6c88a12a402c..7498380300c7 100644
--- a/winaccessibility/source/service/ResIDGenerator.cxx
+++ b/winaccessibility/source/service/ResIDGenerator.cxx
@@ -25,7 +25,7 @@ ResIDGenerator::~ResIDGenerator() {}
 
 /**
    * SubList stores those IDs that were ever generated and deleted, the method
-   * return the ID from subList first if subList is not empty,else return ++max.
+   * return the ID from subList first if subList is not empty, else return m_nMin--.
    * Add the obsolete IDs by calling SetSub method
    *
    * @param
@@ -39,8 +39,8 @@ long ResIDGenerator::GenerateNewResID()
         subList.pop_front();
         return nRes;
     }
-    assert(max < LONG_MAX);
-    return -(++max);
+    assert(m_nMin > LONG_MIN);
+    return m_nMin--;
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */