diff --git a/rtdata/languages/default b/rtdata/languages/default
index 773f7768b..821a6fb60 100644
--- a/rtdata/languages/default
+++ b/rtdata/languages/default
@@ -3320,6 +3320,7 @@ TP_PCVIGNETTE_ROUNDNESS_TOOLTIP;Roundness:\n0 = rectangle,\n50 = fitted ellipse,
 TP_PCVIGNETTE_STRENGTH;Strength
 TP_PCVIGNETTE_STRENGTH_TOOLTIP;Filter strength in stops (reached in corners).
 TP_PDSHARPENING_LABEL;Capture Sharpening
+TP_PERSPECTIVE_CONTROL_LINE_APPLY_INVALID_TOOLTIP;At least two horizontal or two vertical control lines required.
 TP_PERSPECTIVE_CAMERA_CROP_FACTOR;Crop factor
 TP_PERSPECTIVE_CAMERA_FOCAL_LENGTH;Focal length
 TP_PERSPECTIVE_CAMERA_FRAME;Correction
diff --git a/rtgui/controllines.cc b/rtgui/controllines.cc
index c078b4322..e4ef9e9f7 100644
--- a/rtgui/controllines.cc
+++ b/rtgui/controllines.cc
@@ -36,6 +36,7 @@ ControlLineManager::ControlLineManager():
     draw_mode(false),
     drawing_line(false),
     edited(false),
+    horizontalCount(0), verticalCount(0),
     prev_obj(-1),
     selected_object(-1)
 {
@@ -84,6 +85,16 @@ size_t ControlLineManager::size(void) const
     return control_lines.size();
 }
 
+size_t ControlLineManager::getHorizontalCount(void) const
+{
+    return horizontalCount;
+}
+
+size_t ControlLineManager::getVerticalCount(void) const
+{
+    return verticalCount;
+}
+
 bool ControlLineManager::button1Pressed(int modifierKey)
 {
     EditDataProvider* dataProvider = getEditProvider();
@@ -164,9 +175,13 @@ bool ControlLineManager::pick1(bool picked)
     if (line.type == rtengine::ControlLine::HORIZONTAL) {
         line.icon = line.icon_v;
         line.type = rtengine::ControlLine::VERTICAL;
+        horizontalCount--;
+        verticalCount++;
     } else if (line.type == rtengine::ControlLine::VERTICAL) {
         line.icon = line.icon_h;
         line.type = rtengine::ControlLine::HORIZONTAL;
+        horizontalCount++;
+        verticalCount--;
     }
 
     visibleGeometry[object_id - 1] = line.icon.get();
@@ -405,6 +420,11 @@ void ControlLineManager::addLine(Coord begin, Coord end,
     EditSubscriber::mouseOverGeometry.push_back(control_line->end.get());
 
     control_lines.push_back(std::move(control_line));
+    if (type == rtengine::ControlLine::HORIZONTAL) {
+        horizontalCount++;
+    } else {
+        verticalCount++;
+    }
 }
 
 void ControlLineManager::autoSetLineType(int object_id)
@@ -437,6 +457,13 @@ void ControlLineManager::autoSetLineType(int object_id)
     if (type != line.type) { // Need to update line type.
         line.type = type;
         line.icon = icon;
+        if (type == rtengine::ControlLine::HORIZONTAL) {
+            horizontalCount++;
+            verticalCount--;
+        } else {
+            horizontalCount--;
+            verticalCount++;
+        }
         visibleGeometry[line_id * ::ControlLine::OBJ_COUNT + 1] =
             line.icon.get();
     }
@@ -448,6 +475,7 @@ void ControlLineManager::removeAll(void)
     mouseOverGeometry.erase(mouseOverGeometry.begin() + 1,
                             mouseOverGeometry.end());
     control_lines.clear();
+    horizontalCount = verticalCount = 0;
     prev_obj = -1;
     selected_object = -1;
     edited = true;
@@ -470,6 +498,11 @@ void ControlLineManager::removeLine(size_t line_id)
         mouseOverGeometry.begin() + ::ControlLine::OBJ_COUNT * line_id
         + ::ControlLine::OBJ_COUNT + 1
     );
+    if (control_lines[line_id]->type == rtengine::ControlLine::HORIZONTAL) {
+        horizontalCount--;
+    } else {
+        verticalCount--;
+    }
     control_lines.erase(control_lines.begin() + line_id);
 
     edited = true;
diff --git a/rtgui/controllines.h b/rtgui/controllines.h
index 2b2d179a4..578118eb7 100644
--- a/rtgui/controllines.h
+++ b/rtgui/controllines.h
@@ -52,6 +52,7 @@ protected:
     bool draw_mode;
     bool drawing_line;
     bool edited;
+    size_t horizontalCount, verticalCount;
     Cairo::RefPtr<RTSurface> line_icon_h, line_icon_v;
     Cairo::RefPtr<RTSurface> line_icon_h_prelight, line_icon_v_prelight;
     int prev_obj;
@@ -87,6 +88,10 @@ public:
     ~ControlLineManager();
 
     bool getEdited(void) const;
+    /** Returns the number of horizontal control lines. */
+    size_t getHorizontalCount(void) const;
+    /** Returns the number of vertical control lines. */
+    size_t getVerticalCount(void) const;
     void removeAll(void);
     /** Sets whether or not the lines are visible and interact-able. */
     void setActive(bool active);
diff --git a/rtgui/perspective.cc b/rtgui/perspective.cc
index 8db91ee2e..e77c622cd 100644
--- a/rtgui/perspective.cc
+++ b/rtgui/perspective.cc
@@ -351,6 +351,8 @@ void PerspCorrection::read (const ProcParams* pp, const ParamsEdited* pedited)
         method->set_active (1);
     }
 
+    updateApplyDeleteButtons();
+
     enableListener ();
 }
 
@@ -739,11 +741,29 @@ void PerspCorrection::setEditProvider(EditDataProvider* provider)
 
 void PerspCorrection::lineChanged(void)
 {
+    updateApplyDeleteButtons();
+
     if (listener) {
         listener->panelChanged(EvPerspControlLines, M("HISTORY_CHANGED"));
     }
 }
 
+void PerspCorrection::updateApplyDeleteButtons(void)
+{
+    if (batchMode) {
+        return;
+    }
+
+    bool edit_mode = lines_button_edit->get_active();
+    bool enough_lines = lines->getHorizontalCount() >= 2 || lines->getVerticalCount() >= 2;
+    const auto &tooltip = M("GENERAL_APPLY")
+        + ((edit_mode && !enough_lines) ? "\n\n" + M("TP_PERSPECTIVE_CONTROL_LINE_APPLY_INVALID_TOOLTIP") : "");
+
+    lines_button_apply->set_sensitive(edit_mode && enough_lines);
+    lines_button_apply->set_tooltip_text(tooltip);
+    lines_button_erase->set_sensitive(edit_mode && lines->size() > 0);
+}
+
 void PerspCorrection::linesApplyButtonPressed(void)
 {
     if (method->get_active_row_number() == 1) {
@@ -784,6 +804,7 @@ void PerspCorrection::linesEditButtonPressed(void)
             panel_listener->controlLineEditModeChanged(false);
         }
     }
+    updateApplyDeleteButtons();
 }
 
 void PerspCorrection::linesEraseButtonPressed(void)
@@ -795,6 +816,8 @@ void PerspCorrection::requestApplyControlLines(void)
 {
     if (lines_button_apply->is_sensitive()) {
         linesApplyButtonPressed();
+    } else if (lines_button_edit->get_active()) {
+        lines_button_edit->set_active(false);
     }
 }
 
diff --git a/rtgui/perspective.h b/rtgui/perspective.h
index 6f4a4ff52..3368b6282 100644
--- a/rtgui/perspective.h
+++ b/rtgui/perspective.h
@@ -96,6 +96,7 @@ protected:
     void tweakParams(rtengine::procparams::ProcParams &pparams) override;
     void setCamBasedEventsActive (bool active = true);
     void setFocalLengthValue (const rtengine::procparams::ProcParams* pparams, const rtengine::FramesMetaData* metadata);
+    void updateApplyDeleteButtons(void);
 
 public: