diff --git a/4dev/tests/Debug/CoreLibsDebugSupportTest.php b/4dev/tests/Debug/CoreLibsDebugSupportTest.php
index ab74df7d..74ed67ed 100644
--- a/4dev/tests/Debug/CoreLibsDebugSupportTest.php
+++ b/4dev/tests/Debug/CoreLibsDebugSupportTest.php
@@ -513,7 +513,7 @@ final class CoreLibsDebugSupportTest extends TestCase
 	public function testGetCallerMethodList(array $expected): void
 	{
 		$compare = Support::getCallerMethodList();
-		// 10: legact
+		// 10: legacy
 		// 11: direct
 		// 12: full call
 		switch (count($compare)) {
@@ -571,6 +571,31 @@ final class CoreLibsDebugSupportTest extends TestCase
 		}
 	}
 
+	/**
+	 * Undocumented function
+	 *
+	 * @cover ::getCallStack
+	 * @testdox getCallStack check if it returns data [$_dataName]
+	 *
+	 * @return void
+	 */
+	public function testGetCallStack(): void
+	{
+		$call_stack = Support::getCallStack();
+		// print "Get CALL: " . print_r(Support::getCallStack(), true) . "\n";
+		if ($call_stack < 8) {
+			$this->assertFalse(true, 'getCallStack too low: 8');
+		} else {
+			$this->assertTrue(true, 'getCallSteck ok');
+		}
+		// just test top entry
+		$first = array_shift($call_stack);
+		$this->assertStringEndsWith(
+			':tests\CoreLibsDebugSupportTest->testGetCallStack',
+			$first,
+		);
+	}
+
 	/**
 	 * test the lowest one (one above base)
 	 *
diff --git a/www/admin/class_test.datetime.php b/www/admin/class_test.datetime.php
index 55707bc0..7255c368 100644
--- a/www/admin/class_test.datetime.php
+++ b/www/admin/class_test.datetime.php
@@ -470,7 +470,7 @@ function intervalStringFormatDeprecated(
 			// on first hit turn off (full off)
 			if ($value) {
 				$skip_last_zero = null;
-			} elseif (!$value && $skip_last_zero === false) {
+			} elseif ($skip_last_zero === false) {
 				$zero_last_list[] = $part;
 			}
 			// build format
diff --git a/www/admin/class_test.debug.php b/www/admin/class_test.debug.php
index a19d8b9c..8141d383 100644
--- a/www/admin/class_test.debug.php
+++ b/www/admin/class_test.debug.php
@@ -170,6 +170,8 @@ class TestL
 	{
 		print "* GETCALLERCLASS(INSIDE CLASS): " . \CoreLibs\Debug\Support::getCallerClass() . "<br>";
 		print "* GETCALLERTOPCLASS(INSIDE CLASS): " . \CoreLibs\Debug\Support::getCallerTopLevelClass() . "<br>";
+		print "* GETCALLSTACK(INSIDE CLASS): <pre>"
+			. DebugSupport::prAr(\CoreLibs\Debug\Support::getCallStack()) . "</pre><br>";
 		$this->log->debug('TESTL', 'Logging in class testL' . ($ts !== null ? ': ' . $ts : ''));
 		$this->log->debug('TESTL', 'Some other message');
 		return true;
@@ -193,6 +195,8 @@ class TestR extends TestL
 	{
 		print "** GETCALLERCLASS(INSIDE EXTND CLASS): " . \CoreLibs\Debug\Support::getCallerClass() . "<br>";
 		print "** GETCALLERTOPCLASS(INSIDE EXTND CLASS): " . \CoreLibs\Debug\Support::getCallerTopLevelClass() . "<br>";
+		print "** GETCALLSTACK(INSIDE EXTND CLASS): <pre>"
+			. DebugSupport::prAr(\CoreLibs\Debug\Support::getCallStack()) . "</pre><br>";
 		$this->log->debug('TESTR', 'Logging in class testR (extends testL)');
 		$this->test('TESTR INSIDE');
 		$this->log->debug('TESTR', 'Array: '
diff --git a/www/lib/CoreLibs/Debug/Support.php b/www/lib/CoreLibs/Debug/Support.php
index 456be11c..affec0f7 100644
--- a/www/lib/CoreLibs/Debug/Support.php
+++ b/www/lib/CoreLibs/Debug/Support.php
@@ -295,8 +295,7 @@ class Support
 	 * Will start with start_level to skip unwanted from stack
 	 * Defaults to skip level 0 wich is this methid
 	 *
-	 * @param  integer $start_level From what level on, as defaul starts with 1
-	 *                              to exclude self
+	 * @param  integer $start_level [=1] From what level on, starts with 1 to exclude self
 	 * @return array<mixed>         All method names in list where max is last called
 	 */
 	public static function getCallerMethodList(int $start_level = 1): array
@@ -304,15 +303,46 @@ class Support
 		$traces = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS);
 		$methods = [];
 		foreach ($traces as $level => $data) {
-			if ($level >= $start_level) {
-				if (!empty($data['function'])) {
-					array_unshift($methods, $data['function']);
-				}
+			if ($level < $start_level) {
+				continue;
+			}
+			if (!empty($data['function'])) {
+				array_unshift($methods, $data['function']);
 			}
 		}
 		return $methods;
 	}
 
+	/**
+	 * Get the full call stack from a certain starting level
+	 * The return string is
+	 * file:line:class->method
+	 *
+	 * Note that '::' is used for static calls
+	 *
+	 * @param  int   $start_level [=1] starts with 1 to exclude itself
+	 * @return array<string>      string with file, line, class and method
+	 */
+	public static function getCallStack(int $start_level = 1): array
+	{
+		$call_stack = [];
+		$backtrace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS);
+		foreach ($backtrace as $level => $call_trace) {
+			if ($level < $start_level) {
+				continue;
+			}
+			$call_stack[] =
+				($call_trace['file'] ?? 'n/f') . ':'
+				. ($call_trace['line'] ?? '-') . ':'
+				. (!empty($call_trace['class']) ?
+					$call_trace['class'] . ($call_trace['type'] ?? '') :
+					''
+				)
+				. $call_trace['function'];
+		}
+		return $call_stack;
+	}
+
 	/**
 	 * Get the current class where this function is called
 	 * Is mostly used in debug log statements to get the class where the debug