diff --git a/src/debugger/Debugger.cxx b/src/debugger/Debugger.cxx
index fdbb5e3f4..16e03b407 100644
--- a/src/debugger/Debugger.cxx
+++ b/src/debugger/Debugger.cxx
@@ -704,16 +704,20 @@ string Debugger::builtinHelp() const
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void Debugger::getCompletions(const char* in, StringList& list) const
 {
-  for(const auto& iter: myFunctions)
+  // skip if filter equals "_" only
+  if(!BSPF::equalsIgnoreCase(in, "_"))
   {
-    const char* l = iter.first.c_str();
-    if(BSPF::matches(l, in))
-      list.push_back(l);
-  }
+    for(const auto& iter : myFunctions)
+    {
+      const char* l = iter.first.c_str();
+      if(BSPF::matches(l, in))
+        list.push_back(l);
+    }
 
-  for(int i = 0; pseudo_registers[i][0] != 0; ++i)
-    if(BSPF::matches(pseudo_registers[i][0], in))
-      list.push_back(pseudo_registers[i][0]);
+    for(int i = 0; pseudo_registers[i][0] != 0; ++i)
+      if(BSPF::matches(pseudo_registers[i][0], in))
+        list.push_back(pseudo_registers[i][0]);
+  }
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
diff --git a/src/debugger/gui/PromptWidget.cxx b/src/debugger/gui/PromptWidget.cxx
index 5920f98be..7ad406431 100644
--- a/src/debugger/gui/PromptWidget.cxx
+++ b/src/debugger/gui/PromptWidget.cxx
@@ -220,6 +220,7 @@ bool PromptWidget::handleKeyDown(StellaKey key, StellaMod mod)
         }
       }
       str[len] = '\0';
+      int strLen = len - lastDelimPos - 1;
 
       StringList list;
       string completionList;
@@ -227,7 +228,7 @@ bool PromptWidget::handleKeyDown(StellaKey key, StellaMod mod)
 
       if(lastDelimPos < 0)
       {
-        // no delimiters, do command completion:
+        // no delimiters, do only command completion:
         const DebuggerParser& parser = instance().debugger().parser();
         parser.getCompletions(str, list);
 
@@ -249,11 +250,15 @@ bool PromptWidget::handleKeyDown(StellaKey key, StellaMod mod)
         }
         else
         {
-          // we got a delimiter, so this must be a label or a function
-          const Debugger& dbg = instance().debugger();
+          // do not show ALL labels without any filter as it makes no sense
+          if(strLen > 0)
+          {
+            // we got a delimiter, so this must be a label or a function
+            const Debugger& dbg = instance().debugger();
 
-          dbg.cartDebug().getCompletions(str + lastDelimPos + 1, list);
-          dbg.getCompletions(str + lastDelimPos + 1, list);
+            dbg.cartDebug().getCompletions(str + lastDelimPos + 1, list);
+            dbg.getCompletions(str + lastDelimPos + 1, list);
+          }
         }
 
         if(list.size() < 1)
@@ -266,6 +271,8 @@ bool PromptWidget::handleKeyDown(StellaKey key, StellaMod mod)
         prefix = getCompletionPrefix(list);
       }
 
+      // TODO: tab through list
+
       if(list.size() == 1)
       {
         // add to buffer as though user typed it (plus a space)
@@ -927,8 +934,7 @@ string PromptWidget::getCompletionPrefix(const StringList& completions)
 
       for(uInt32 j = i + 1; j < completions.size(); j++)
       {
-        string s2 = completions[j];
-        if(!BSPF::startsWithIgnoreCase(s2, find))
+        if(!BSPF::startsWithIgnoreCase(completions[j], find))
           return s1.substr(0, len - 1);
       }
     }