diff --git a/sources/qet.cpp b/sources/qet.cpp
index 2260d5d3a..8f9b79908 100644
--- a/sources/qet.cpp
+++ b/sources/qet.cpp
@@ -255,6 +255,23 @@ bool QET::attributeIsAReal(
 	return(true);
 }
 
+/**
+	@brief QET::infoFlagIsTrue
+	@see the header comment for why this exists rather than a bare
+	== "true" comparison.
+	@param value the raw elementInformations string to test
+	@return true if @p value, trimmed and case-folded, is one of the
+	truthy spellings this codebase already accepts elsewhere
+*/
+bool QET::infoFlagIsTrue(const QString &value)
+{
+	const QString v = value.trimmed().toLower();
+	return v == QLatin1String("true")
+		|| v == QLatin1String("1")
+		|| v == QLatin1String("yes")
+		|| v == QLatin1String("on");
+}
+
 /**
 	@brief QET::ElementsAndConductorsSentence
 	Permet de composer rapidement la proposition "x elements et y conducteurs"
diff --git a/sources/qet.h b/sources/qet.h
index da544ac13..cb5a8a0a8 100644
--- a/sources/qet.h
+++ b/sources/qet.h
@@ -161,6 +161,22 @@ namespace QET {
 	bool orthogonalProjection(const QPointF &, const QLineF &, QPointF * = nullptr);
 	bool attributeIsAnInteger(const QDomElement &, const QString& , int * = nullptr);
 	bool attributeIsAReal(const QDomElement &, const QString& , qreal * = nullptr);
+		/**
+			Whether an elementInformations flag (auto_num_locked,
+			potential_isolating, exclude_from_bom, ...) counts as "on".
+			Case-insensitive and tolerant of surrounding whitespace, and
+			accepts the same set of truthy spellings ("true", "1", "yes",
+			"on") that element_nomenclature_view's SQL predicate for
+			exclude_from_bom already does -- see
+			projectDataBase::createElementNomenclatureView(). These flags
+			are only ever written by this app's own checkboxes as literal
+			"true"/"false" today, but a bare == "true" comparison silently
+			treats anything else -- "True", "TRUE", a trailing space from
+			a hand-edited file, a value some other tool wrote -- as off,
+			with no error and no visible difference from the checkbox
+			being genuinely unticked (discussion #785).
+		*/
+	bool infoFlagIsTrue(const QString &value);
 	QString ElementsAndConductorsSentence(int elements=0,
 										  int conductors=0,
 										  int indi_texts=0,
diff --git a/sources/qetgraphicsitem/terminal.cpp b/sources/qetgraphicsitem/terminal.cpp
index f559e326d..a1c9af780 100644
--- a/sources/qetgraphicsitem/terminal.cpp
+++ b/sources/qetgraphicsitem/terminal.cpp
@@ -16,6 +16,7 @@
 	along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
 */
 #include "../qetgraphicsitem/terminal.h"
+#include "../qet.h"
 #include "../qetproject.h"
 #include "../conductorautonumerotation.h"
 #include "../diagram.h"
@@ -986,7 +987,7 @@ QList<Terminal *> relatedPotentialTerminal (
 	else if (terminal -> parentElement() -> linkType() & Element::Terminale)
 	{
 		// English: Check if the user activated the potential isolation checkbox for this terminal
-		if (terminal->parentElement()->elementInformations().value(QStringLiteral("potential_isolating")).toString() == QLatin1String("true")) {
+		if (QET::infoFlagIsTrue(terminal->parentElement()->elementInformations().value(QStringLiteral("potential_isolating")).toString())) {
 			// English: Potential is isolated. Return an empty list so it does not propagate to the other side.
 			return QList<Terminal *>();
 		}
diff --git a/sources/ui/elementinfowidget.cpp b/sources/ui/elementinfowidget.cpp
index 0107c9664..f67f2bd85 100644
--- a/sources/ui/elementinfowidget.cpp
+++ b/sources/ui/elementinfowidget.cpp
@@ -16,6 +16,7 @@
 	along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
 */
 #include "elementinfowidget.h"
+#include "../qet.h"
 #include <QCheckBox>
 #include <QPushButton>
 #include "../diagram.h"
@@ -366,12 +367,12 @@ void ElementInfoWidget::updateUi()
 	// Load the lock status for auto numbering
 	if (m_element->elementData().m_type == ElementData::Terminal) {
 		QString lock_value = element_info.value(QStringLiteral("auto_num_locked")).toString();
-		ui->m_auto_num_locked_cb->setChecked(lock_value == QLatin1String("true"));
+		ui->m_auto_num_locked_cb->setChecked(QET::infoFlagIsTrue(lock_value));
 
 		// English: Load the potential isolating status from the element information mapping
 		if (m_potential_isolating_cb) {
 			QString isolating_value = element_info.value(QStringLiteral("potential_isolating")).toString();
-			m_potential_isolating_cb->setChecked(isolating_value == QLatin1String("true"));
+			m_potential_isolating_cb->setChecked(QET::infoFlagIsTrue(isolating_value));
 		}
 	}
 	// English: Load the BOM exclusion status from the element information mapping
diff --git a/sources/ui/terminalnumberingdialog.cpp b/sources/ui/terminalnumberingdialog.cpp
index 38c8a655d..85f299214 100644
--- a/sources/ui/terminalnumberingdialog.cpp
+++ b/sources/ui/terminalnumberingdialog.cpp
@@ -1,5 +1,6 @@
 #include "terminalnumberingdialog.h"
 #include "ui_terminalnumberingdialog.h"
+#include "../qet.h"
 #include "../qetproject.h"
 #include "../diagram.h"
 #include "../qetgraphicsitem/element.h"
@@ -34,7 +35,7 @@ TerminalNumberingDialog::TerminalNumberingDialog(QWidget *parent, QETProject *pr
                     if (elmt->elementData().m_type == ElementData::Terminal) {
                         // Ignore locked terminals
                         DiagramContext info = elmt->elementInformations();
-                        if (info.value(QStringLiteral("auto_num_locked")).toString() == QLatin1String("true")) {
+                        if (QET::infoFlagIsTrue(info.value(QStringLiteral("auto_num_locked")).toString())) {
                             continue;
                         }
 
@@ -158,7 +159,7 @@ QUndoCommand* TerminalNumberingDialog::getUndoCommand(QETProject *project) const
                     DiagramContext info = elmt->elementInformations();
 
                     // Ignore locked terminals (if the user checked a 'lock' property)
-                    if (info.value(QStringLiteral("auto_num_locked")).toString() == QLatin1String("true")) {
+                    if (QET::infoFlagIsTrue(info.value(QStringLiteral("auto_num_locked")).toString())) {
                         continue;
                     }