From fae1ca5f044df291717616bc188ebccb69ec7848 Mon Sep 17 00:00:00 2001
From: unknown <maartentenvelden@hotmail.com>
Date: Tue, 30 Jan 2024 21:56:47 +0100
Subject: [PATCH] Tried to fix invisible tabs issue upon maximizing window but
 this doesn't seem to entirely work, submitting this to create a pull request
 that another developer can test

---
 src/TabBar.cpp | 30 +++++++++++++++++++++++++++---
 src/TabBar.h   |  1 +
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/src/TabBar.cpp b/src/TabBar.cpp
index ddcb1010..b7500b2e 100644
--- a/src/TabBar.cpp
+++ b/src/TabBar.cpp
@@ -55,6 +55,7 @@ CTabBar::CTabBar(HINSTANCE hInst)
     , m_tabBarDefaultProc(nullptr)
     , m_tabBarSpinDefaultProc(nullptr)
     , m_spin(nullptr)
+    , m_bIsSpinVisible(false)
     , m_currentHoverTabItem(-1)
     , m_bIsCloseHover(false)
     , m_whichCloseClickDown(-1)
@@ -483,7 +484,7 @@ LRESULT CTabBar::RunProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 
             DrawMainBorder(&dis);
 
-            if (m_spin)
+            if (m_bIsSpinVisible)
             {
                 RECT rcSpin{};
                 GetWindowRect(m_spin, &rcSpin);
@@ -677,7 +678,7 @@ LRESULT CTabBar::RunProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
             auto index = GetTabIndexAt(xPos, yPos);
             RECT rcItem{};
             TabCtrl_GetItemRect(*this, index, &rcItem);
-            if (m_spin)
+            if (m_bIsSpinVisible)
             {
                 RECT rcSpin{};
                 GetWindowRect(m_spin, &rcSpin);
@@ -754,7 +755,7 @@ LRESULT CTabBar::RunProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
                 RECT rPage{};
                 GetClientRect(*this, &rPage);
                 TabCtrl_AdjustRect(*this, FALSE, &rPage);
-                if (m_spin)
+                if (m_bIsSpinVisible)
                 {
                     RECT rcSpin{};
                     GetWindowRect(m_spin, &rcSpin);
@@ -1272,6 +1273,13 @@ LRESULT CTabBar::TabBarSpin_Proc(HWND hwnd, UINT message, WPARAM wParam, LPARAM
     {
         case WM_PAINT:
         {
+            // as WM_SHOWWINDOW is only ever sent with wParam == FALSE, use WM_PAINT instead of WM_SHOWWINDOW with wParam == TRUE
+            // alternatives might be WM_NCPAINT or 1125, which also both seem to be only sent when updown control is unhidden
+            if (!pTab->m_bIsSpinVisible)
+            {
+                pTab->m_bIsSpinVisible = true;
+            }
+
             PAINTSTRUCT ps;
             BeginPaint(hwnd, &ps);
             HDC  hdc = ps.hdc;
@@ -1472,8 +1480,23 @@ LRESULT CTabBar::TabBarSpin_Proc(HWND hwnd, UINT message, WPARAM wParam, LPARAM
             InvalidateRect(hwnd, nullptr, false);
         }
         break;
+        case WM_SHOWWINDOW:
+        {
+            if (wParam == FALSE) //< checked and is only ever sent with wParam == FALSE
+            {
+                pTab->m_bIsSpinVisible = false;
+            }
+            /*
+            else
+            {
+                pTab->m_bIsSpinVisible = true;
+            }
+            */
+            break;
+        }
         case WM_DESTROY:
         {
+            pTab->m_bIsSpinVisible = false;
             pTab->m_spin = nullptr;
             break;
         }
@@ -1533,6 +1556,7 @@ void CTabBar::SubclassSpinBox()
 
                     pThis->m_tabBarSpinDefaultProc = reinterpret_cast<WNDPROC>(::SetWindowLongPtr(hChild, GWLP_WNDPROC, reinterpret_cast<LONG_PTR>(TabBarSpin_Proc)));
                     pThis->m_spin                  = hChild;
+                    pThis->m_bIsSpinVisible        = true;
                     return FALSE;
                 }
                 return TRUE;
diff --git a/src/TabBar.h b/src/TabBar.h
index 322e0971..45a0754a 100644
--- a/src/TabBar.h
+++ b/src/TabBar.h
@@ -145,6 +145,7 @@ class CTabBar : public CWindow
     WNDPROC                          m_tabBarDefaultProc;
     WNDPROC                          m_tabBarSpinDefaultProc;
     HWND                             m_spin;
+    bool                             m_bIsSpinVisible;
 
     RECT                             m_currentHoverTabRect;
     int                              m_currentHoverTabItem;