use QStandardPaths locations for all file dialogs.

src/TextInputWidget.cpp

@@ -626,8 +626,9 @@ TextInputWidget::command(QString command, QString args)
 void
 TextInputWidget::openFileSelection()
 {
+        const QString homeFolder = QStandardPaths::writableLocation(QStandardPaths::HomeLocation);
         const auto fileName =
-          QFileDialog::getOpenFileName(this, tr("Select a file"), "", tr("All Files (*)"));
+          QFileDialog::getOpenFileName(this, tr("Select a file"), homeFolder, tr("All Files (*)"));
 
         if (fileName.isEmpty())
                 return;

src/UserSettingsPage.cpp

@@ -27,6 +27,7 @@
 #include <QPushButton>
 #include <QScrollArea>
 #include <QSettings>
+#include <QStandardPaths>
 #include <QString>
 #include <QTextStream>
 
@@ -513,7 +514,9 @@ UserSettingsPage::paintEvent(QPaintEvent *)
 void
 UserSettingsPage::importSessionKeys()
 {
-        auto fileName = QFileDialog::getOpenFileName(this, tr("Open Sessions File"), "", "");
+        const QString homeFolder = QStandardPaths::writableLocation(QStandardPaths::HomeLocation);
+        const QString fileName =
+          QFileDialog::getOpenFileName(this, tr("Open Sessions File"), homeFolder, "");
 
         QFile file(fileName);
         if (!file.open(QIODevice::ReadOnly)) {
@@ -572,7 +575,8 @@ UserSettingsPage::exportSessionKeys()
         }
 
         // Open file dialog to save the file.
-        auto fileName =
+        const QString homeFolder = QStandardPaths::writableLocation(QStandardPaths::HomeLocation);
+        const QString fileName =
           QFileDialog::getSaveFileName(this, tr("File to save the exported session keys"), "", "");
 
         QFile file(fileName);

src/dialogs/RoomSettings.cpp

@@ -11,6 +11,7 @@
 #include <QPushButton>
 #include <QShortcut>
 #include <QShowEvent>
+#include <QStandardPaths>
 #include <QStyleOption>
 #include <QVBoxLayout>
 
@@ -740,8 +741,10 @@ RoomSettings::resetErrorLabel()
 void
 RoomSettings::updateAvatar()
 {
-        const auto fileName =
+        const QString picturesFolder =
-          QFileDialog::getOpenFileName(this, tr("Select an avatar"), "", tr("All Files (*)"));
+          QStandardPaths::writableLocation(QStandardPaths::PicturesLocation);
+        const QString fileName = QFileDialog::getOpenFileName(
+          this, tr("Select an avatar"), picturesFolder, tr("All Files (*)"));
 
         if (fileName.isEmpty())
                 return;

src/timeline/TimelineModel.cpp

@@ -1299,7 +1299,8 @@ TimelineModel::saveMedia(QString eventId) const
         }
 
         const QString filterString = QMimeDatabase().mimeTypeForName(mimeType).filterString();
-        const QString downloadsFolder = QStandardPaths::writableLocation(QStandardPaths::DownloadLocation);
+        const QString downloadsFolder =
+          QStandardPaths::writableLocation(QStandardPaths::DownloadLocation);
         const QString openLocation = downloadsFolder + "/" + originalFilename;
 
         const QString filename = QFileDialog::getSaveFileName(