Set the initial task button text (and icon) correctly.

debian/changelog

@@ -23,6 +23,9 @@ lxqt-panel (0.12.0-8ubuntu1) UNRELEASED; urgency=medium
     - Add Move and Resize items in the task-button context menu.
       + add-move-resize-items.patch
       + Upstream commit b69fe72.
+    - Set the initial task button text (and icon) correctly.
+      + set-initial-task-button-correctly.patch
+      + Upstream commit 563d6bf.
 
  -- Simon Quigley <tsimonq2@ubuntu.com>  Mon, 05 Feb 2018 19:00:18 -0600
 

debian/patches/series

@@ -8,3 +8,4 @@ use-specific-panel-icon.patch
 fix-memory-leaks.patch
 avoid-infinite-recursion-icons.patch
 add-move-resize-items.patch
+set-initial-task-button-correctly.patch

debian/patches/set-initial-task-button-correctly.patch

@@ -0,0 +1,27 @@
+Description: Set the initial task button text (and icon) correctly
+ Detailed explanation:
+ .
+ When a window shows up, the signal `KWindowSystem::stackingOrderChanged` is emitted *before* `KWindowSystem::windowAdded`. The former signal is connected to the function `LXQtTaskBar::refreshTaskList()`, which calls the functions `LXQtTaskBar::addWindow()` and `LXQtTaskBar::removeWindow()` to add and remove monitored windows.
+ .
+ Connecting `LXQtTaskBar::refreshTaskList()` to the signal `KWindowSystem::stackingOrderChanged` not only is redundant but also causes a problem:
+ .
+ (1) It's redundant because the job of adding *new* windows should be done by `LXQtTaskBar::onWindowAdded()` connected to the signal `KWindowSystem::windowAdded`. However, with the current code, `LXQtTaskBar::addWindow()` is never called by that function because the new window is already added through `KWindowSystem::stackingOrderChanged`. Similarly, `LXQtTaskBar::onWindowRemoved()` should be responsible for removing windows by being connected to the signal `KWindowSystem::windowRemoved`.
+ .
+ (2) More importantly, as the window name can change in the short interval between the emissions of `KWindowSystem::stackingOrderChanged` and `KWindowSystem::windowAdded`, the corresponding taskbar button may get a wrong text. The reason is that the signal `WindowSystem::windowChanged` announces changes only starting from the emission of `KWindowSystem::windowAdded`. (Theoretically, the initial icon might also be wrong but that's rarer).
+ .
+ Here, the connection to `KWindowSystem::stackingOrderChanged` is removed, so that the initial task button text/icon is set correctly. In this way, several useless calls to `LXQtTaskBar::refreshTaskList()` are also prevented when a window is shown/closed or focused/unfocused.
+Author: Tsu Jan <tsujan2000@gmail.com>
+Origin: backport
+Bug: https://github.com/lxde/lxqt/issues/1303
+Applied-Upstream: commit:563d6bf
+Last-Update: 2018-02-05
+--- a/plugin-taskbar/lxqttaskbar.cpp
++++ b/plugin-taskbar/lxqttaskbar.cpp
+@@ -93,7 +93,6 @@ LXQtTaskBar::LXQtTaskBar(ILXQtPanelPlugi
+     connect(mSignalMapper, static_cast<void (QSignalMapper::*)(int)>(&QSignalMapper::mapped), this, &LXQtTaskBar::activateTask);
+     QTimer::singleShot(0, this, &LXQtTaskBar::registerShortcuts);
+ 
+-    connect(KWindowSystem::self(), SIGNAL(stackingOrderChanged()), SLOT(refreshTaskList()));
+     connect(KWindowSystem::self(), static_cast<void (KWindowSystem::*)(WId, NET::Properties, NET::Properties2)>(&KWindowSystem::windowChanged)
+             , this, &LXQtTaskBar::onWindowChanged);
+     connect(KWindowSystem::self(), &KWindowSystem::windowAdded, this, &LXQtTaskBar::onWindowAdded);