chatgui: clear clipboard before setText for reliable copy on Linux

tools/chatgui/src/chatview.cpp

@@ -133,6 +133,7 @@ void ChatView::copySelection() {
         QString text = idx.data(MsgTextRole).toString();
         if (m_textSel.startChar >= 0 && m_textSel.endChar > m_textSel.startChar)
             text = text.mid(m_textSel.startChar, m_textSel.endChar - m_textSel.startChar);
+        QApplication::clipboard()->clear(QClipboard::Clipboard);
         QApplication::clipboard()->setText(text);
     } else {
         QString r;
@@ -145,6 +146,7 @@ void ChatView::copySelection() {
             r += idx.data(MsgAuthorRole).toString() + ": ";
             r += idx.data(MsgTextRole).toString();
         }
+        QApplication::clipboard()->clear(QClipboard::Clipboard);
         QApplication::clipboard()->setText(r);
     }
 }

tools/chatgui/src/invitedialog.cpp

@@ -27,9 +27,12 @@ InviteDialog::InviteDialog(const QString& link, QWidget* parent)
     auto *copyBtn = new QPushButton("Скопировать", this);
     connect(copyBtn, &QPushButton::clicked, this, [this, linkEdit]() {
         QClipboard* cb = QApplication::clipboard();
+        cb->clear(QClipboard::Clipboard);
         cb->setText(m_link, QClipboard::Clipboard);
-        if (cb->supportsSelection())
+        if (cb->supportsSelection()) {
+            cb->clear(QClipboard::Selection);
             cb->setText(m_link, QClipboard::Selection);
+        }
         linkEdit->setFocus();
     });
     btnLayout->addWidget(copyBtn);