diff --git a/include/mainwindow.h b/include/mainwindow.h
index bd88cb3a..88439457 100644
--- a/include/mainwindow.h
+++ b/include/mainwindow.h
@@ -194,7 +194,7 @@ private slots:
     void on_actionExport_Stitched_Map_Image_triggered();
     void on_actionExport_Map_Timelapse_Image_triggered();
 
-    void on_comboBox_ConnectionDirection_currentIndexChanged(const QString &arg1);
+    void on_comboBox_ConnectionDirection_currentTextChanged(const QString &arg1);
     void on_spinBox_ConnectionOffset_valueChanged(int offset);
     void on_comboBox_ConnectedMap_currentTextChanged(const QString &mapName);
     void on_pushButton_AddConnection_clicked();
diff --git a/include/ui/regionmapeditor.h b/include/ui/regionmapeditor.h
index cba14251..1dee23f7 100644
--- a/include/ui/regionmapeditor.h
+++ b/include/ui/regionmapeditor.h
@@ -118,8 +118,8 @@ private slots:
     void on_action_Import_CityMap_ImageTiles_triggered();
     void on_tabWidget_Region_Map_currentChanged(int);
     void on_pushButton_RM_Options_delete_clicked();
-    void on_comboBox_RM_ConnectedMap_activated(const QString &);
-    void on_comboBox_RM_Entry_MapSection_activated(const QString &);
+    void on_comboBox_RM_ConnectedMap_textActivated(const QString &);
+    void on_comboBox_RM_Entry_MapSection_textActivated(const QString &);
     void on_spinBox_RM_Entry_x_valueChanged(int);
     void on_spinBox_RM_Entry_y_valueChanged(int);
     void on_spinBox_RM_Entry_width_valueChanged(int);
diff --git a/include/ui/shortcut.h b/include/ui/shortcut.h
index 58980a3b..8989401d 100644
--- a/include/ui/shortcut.h
+++ b/include/ui/shortcut.h
@@ -2,6 +2,7 @@
 #define SHORTCUT_H
 
 #include <QObject>
+#include <QWidget>
 #include <QKeySequence>
 #include <QShortcut>
 
diff --git a/include/ui/tileseteditor.h b/include/ui/tileseteditor.h
index 1af92f35..a65cb75d 100644
--- a/include/ui/tileseteditor.h
+++ b/include/ui/tileseteditor.h
@@ -79,7 +79,7 @@ private slots:
 
     void on_actionRedo_triggered();
 
-    void on_comboBox_metatileBehaviors_activated(const QString &arg1);
+    void on_comboBox_metatileBehaviors_textActivated(const QString &arg1);
 
     void on_lineEdit_metatileLabel_editingFinished();
 
diff --git a/src/config.cpp b/src/config.cpp
index 1d0d55bf..35c1507f 100644
--- a/src/config.cpp
+++ b/src/config.cpp
@@ -37,7 +37,6 @@ void KeyValueConfigBase::load() {
     }
 
     QTextStream in(&file);
-    in.setCodec("UTF-8");
     QList<QString> configLines;
     QRegularExpression re("^(?<key>[^=]+)=(?<value>.*)$");
     while (!in.atEnd()) {
diff --git a/src/core/parseutil.cpp b/src/core/parseutil.cpp
index e45e8b10..79464b8b 100644
--- a/src/core/parseutil.cpp
+++ b/src/core/parseutil.cpp
@@ -34,7 +34,6 @@ QString ParseUtil::readTextFile(const QString &path) {
         return QString();
     }
     QTextStream in(&file);
-    in.setCodec("UTF-8");
     QString text = "";
     while (!in.atEnd()) {
         text += in.readLine() + '\n';
@@ -65,9 +64,9 @@ QList<QStringList> ParseUtil::parseAsm(const QString &filename) {
             // There should not be anything else on the line.
             // gas will raise a syntax error if there is.
         } else {
-            int index = trimmedLine.indexOf(QRegExp("\\s+"));
+            int index = trimmedLine.indexOf(QRegularExpression("\\s+"));
             const QString macro = trimmedLine.left(index);
-            QStringList params(trimmedLine.right(trimmedLine.length() - index).trimmed().split(QRegExp("\\s*,\\s*")));
+            QStringList params(trimmedLine.right(trimmedLine.length() - index).trimmed().split(QRegularExpression("\\s*,\\s*")));
             params.prepend(macro);
             parsed.append(params);
         }
@@ -227,15 +226,16 @@ QString ParseUtil::readCIncbin(const QString &filename, const QString &label) {
 
     text = readTextFile(root + "/" + filename);
 
-    QRegExp *re = new QRegExp(QString(
+    QRegularExpression re(QString(
         "\\b%1\\b"
         "\\s*\\[?\\s*\\]?\\s*=\\s*"
         "INCBIN_[US][0-9][0-9]?"
         "\\(\\s*\"([^\"]*)\"\\s*\\)").arg(label));
 
-    int pos = re->indexIn(text);
+    QRegularExpressionMatch match;
+    qsizetype pos = text.indexOf(re, 0, &match);
     if (pos != -1) {
-        path = re->cap(1);
+        path = match.captured(1);
     }
 
     return path;
diff --git a/src/core/regionmap.cpp b/src/core/regionmap.cpp
index 7d3c8a7e..f8dbcac1 100644
--- a/src/core/regionmap.cpp
+++ b/src/core/regionmap.cpp
@@ -134,7 +134,6 @@ bool RegionMap::readLayout() {
     bool mapNamesQualified = false, mapEntriesQualified = false;
 
     QTextStream in(&file);
-    in.setCodec("UTF-8");
     while (!in.atEnd()) {
         QString line = in.readLine();
         if (line.contains(QRegularExpression(".*sMapName.*="))) {
diff --git a/src/mainwindow.cpp b/src/mainwindow.cpp
index 94584ac1..52c987b8 100644
--- a/src/mainwindow.cpp
+++ b/src/mainwindow.cpp
@@ -425,7 +425,7 @@ void MainWindow::on_lineEdit_filterBox_textChanged(const QString &arg1)
 
 void MainWindow::applyMapListFilter(QString filterText)
 {
-    mapListProxyModel->setFilterRegExp(QRegExp(filterText, Qt::CaseInsensitive, QRegExp::FixedString));
+    mapListProxyModel->setFilterRegularExpression(QRegularExpression(filterText, QRegularExpression::CaseInsensitiveOption));
     if (filterText.isEmpty()) {
         ui->mapList->collapseAll();
     } else {
@@ -629,7 +629,7 @@ bool MainWindow::setMap(QString map_name, bool scrollTreeView) {
 
     if (scrollTreeView) {
         // Make sure we clear the filter first so we actually have a scroll target
-        mapListProxyModel->setFilterRegExp(QString());
+        mapListProxyModel->setFilterRegularExpression(QString());
         ui->mapList->setCurrentIndex(mapListProxyModel->mapFromSource(mapListIndexes.value(map_name)));
         ui->mapList->scrollTo(ui->mapList->currentIndex(), QAbstractItemView::PositionAtCenter);
     }
@@ -2694,7 +2694,7 @@ void MainWindow::showExportMapImageWindow(ImageExporterMode mode) {
     }
 }
 
-void MainWindow::on_comboBox_ConnectionDirection_currentIndexChanged(const QString &direction)
+void MainWindow::on_comboBox_ConnectionDirection_currentTextChanged(const QString &direction)
 {
     editor->updateCurrentConnectionDirection(direction);
 }
diff --git a/src/project.cpp b/src/project.cpp
index e754d5ac..860c1087 100644
--- a/src/project.cpp
+++ b/src/project.cpp
@@ -642,8 +642,8 @@ void Project::setNewMapLayout(Map* map) {
     layout->name = QString("%1_Layout").arg(map->name);
     layout->width = QString::number(getDefaultMapSize());
     layout->height = QString::number(getDefaultMapSize());
-    layout->border_width = DEFAULT_BORDER_WIDTH;
-    layout->border_height = DEFAULT_BORDER_HEIGHT;
+    layout->border_width = QString::number(DEFAULT_BORDER_WIDTH);
+    layout->border_height = QString::number(DEFAULT_BORDER_HEIGHT);
     layout->border_path = QString("data/layouts/%1/border.bin").arg(map->name);
     layout->blockdata_path = QString("data/layouts/%1/map.bin").arg(map->name);
     layout->tileset_primary_label = tilesetLabels["primary"].value(0, "gTileset_General");
@@ -1512,10 +1512,10 @@ void Project::loadTilesetAssets(Tileset* tileset) {
         QString path = tileset->palettePaths.value(i);
         QString text = parser.readTextFile(path);
         if (!text.isNull()) {
-            QStringList lines = text.split(QRegExp("[\r\n]"), Qt::SkipEmptyParts);
+            QStringList lines = text.split(QRegularExpression("[\r\n]"), Qt::SkipEmptyParts);
             if (lines.length() == 19 && lines[0] == "JASC-PAL" && lines[1] == "0100" && lines[2] == "16") {
                 for (int j = 0; j < 16; j++) {
-                    QStringList rgb = lines[j + 3].split(QRegExp(" "), Qt::SkipEmptyParts);
+                    QStringList rgb = lines[j + 3].split(QRegularExpression(" "), Qt::SkipEmptyParts);
                     if (rgb.length() != 3) {
                         logWarn(QString("Invalid tileset palette RGB value: '%1'").arg(lines[j + 3]));
                         palette.append(qRgb((j - 3) * 16, (j - 3) * 16, (j - 3) * 16));
@@ -2327,13 +2327,13 @@ bool Project::readEventScriptLabels() {
 }
 
 QString Project::fixPalettePath(QString path) {
-    path = path.replace(QRegExp("\\.gbapal$"), ".pal");
+    path = path.replace(QRegularExpression("\\.gbapal$"), ".pal");
     return path;
 }
 
 QString Project::fixGraphicPath(QString path) {
-    path = path.replace(QRegExp("\\.lz$"), "");
-    path = path.replace(QRegExp("\\.[1248]bpp$"), ".png");
+    path = path.replace(QRegularExpression("\\.lz$"), "");
+    path = path.replace(QRegularExpression("\\.[1248]bpp$"), ".png");
     return path;
 }
 
@@ -2445,7 +2445,7 @@ void Project::loadEventPixmaps(QList<Event*> objects) {
             QString dimensions_label = gfx_info.value(11);
             QString subsprites_label = gfx_info.value(12);
             QString gfx_label = parser.readCArray("src/data/object_events/object_event_pic_tables.h", pic_label).value(0);
-            gfx_label = gfx_label.section(QRegExp("[\\(\\)]"), 1, 1);
+            gfx_label = gfx_label.section(QRegularExpression("[\\(\\)]"), 1, 1);
             QString path = parser.readCIncbin("src/data/object_events/object_event_graphics.h", gfx_label);
 
             if (!path.isNull()) {
diff --git a/src/ui/customattributestable.cpp b/src/ui/customattributestable.cpp
index b8c2de6c..6723ea0f 100644
--- a/src/ui/customattributestable.cpp
+++ b/src/ui/customattributestable.cpp
@@ -24,7 +24,7 @@ CustomAttributesTable::CustomAttributesTable(Event *event, QWidget *parent) :
     buttonsFrame->layout()->addWidget(addButton);
     buttonsFrame->layout()->addWidget(deleteButton);
     buttonsFrame->layout()->addItem(new QSpacerItem(1, 1, QSizePolicy::Expanding, QSizePolicy::Fixed));
-    buttonsFrame->layout()->setMargin(0);
+    buttonsFrame->layout()->setContentsMargins(0, 0, 0, 0);
     layout->addWidget(buttonsFrame);
 
     this->table = new QTableWidget(this);
diff --git a/src/ui/filterchildrenproxymodel.cpp b/src/ui/filterchildrenproxymodel.cpp
index faff6a23..a08c150c 100644
--- a/src/ui/filterchildrenproxymodel.cpp
+++ b/src/ui/filterchildrenproxymodel.cpp
@@ -9,7 +9,7 @@ FilterChildrenProxyModel::FilterChildrenProxyModel(QObject *parent) :
 bool FilterChildrenProxyModel::filterAcceptsRow(int source_row, const QModelIndex &source_parent) const
 {
     // custom behaviour :
-    if(filterRegExp().isEmpty() == false)
+    if(filterRegularExpression().pattern().isEmpty() == false)
     {
         // get source-model index for current row
         QModelIndex source_index = sourceModel()->index(source_row, this->filterKeyColumn(), source_parent) ;
@@ -27,7 +27,7 @@ bool FilterChildrenProxyModel::filterAcceptsRow(int source_row, const QModelInde
             // check current index itself
             QString key = sourceModel()->data(source_index, filterRole()).toString();
             QString parentKey = sourceModel()->data(source_parent, filterRole()).toString();
-            return key.contains(filterRegExp()) || parentKey.contains(filterRegExp());
+            return key.contains(filterRegularExpression()) || parentKey.contains(filterRegularExpression());
         }
     }
     // parent call for initial behaviour
diff --git a/src/ui/mapimageexporter.cpp b/src/ui/mapimageexporter.cpp
index 216c7db8..24aaa66a 100644
--- a/src/ui/mapimageexporter.cpp
+++ b/src/ui/mapimageexporter.cpp
@@ -4,7 +4,6 @@
 #include "editcommands.h"
 
 #include <QFileDialog>
-#include <QMatrix>
 #include <QImage>
 #include <QPainter>
 #include <QPoint>
diff --git a/src/ui/newtilesetdialog.cpp b/src/ui/newtilesetdialog.cpp
index 0639fab3..3b510dea 100644
--- a/src/ui/newtilesetdialog.cpp
+++ b/src/ui/newtilesetdialog.cpp
@@ -11,8 +11,8 @@ NewTilesetDialog::NewTilesetDialog(Project* project, QWidget *parent) :
     this->setFixedSize(this->width(), this->height());
     this->project = project;
     //only allow characters valid for a symbol
-    QRegExp expression("[_A-Za-z0-9]+$");
-    QRegExpValidator *validator = new QRegExpValidator(expression);
+    QRegularExpression expression("[_A-Za-z0-9]+$");
+    QRegularExpressionValidator *validator = new QRegularExpressionValidator(expression);
     this->ui->nameLineEdit->setValidator(validator);
 
     connect(this->ui->nameLineEdit, &QLineEdit::textChanged, this, &NewTilesetDialog::NameOrSecondaryChanged);
diff --git a/src/ui/noscrollcombobox.cpp b/src/ui/noscrollcombobox.cpp
index 068154d2..fb3abb4d 100644
--- a/src/ui/noscrollcombobox.cpp
+++ b/src/ui/noscrollcombobox.cpp
@@ -10,7 +10,7 @@ NoScrollComboBox::NoScrollComboBox(QWidget *parent)
 
     // Make speed a priority when loading comboboxes.
     setMinimumContentsLength(24);// an arbitrary limit
-    setSizeAdjustPolicy(QComboBox::AdjustToMinimumContentsLength);
+    setSizeAdjustPolicy(QComboBox::AdjustToMinimumContentsLengthWithIcon);
 
     // Allow items to be searched by any part of the word, displaying all matches.
     setEditable(true);// can set to false manually when using
diff --git a/src/ui/regionmapeditor.cpp b/src/ui/regionmapeditor.cpp
index 6d19cb25..a95cb068 100644
--- a/src/ui/regionmapeditor.cpp
+++ b/src/ui/regionmapeditor.cpp
@@ -550,13 +550,13 @@ void RegionMapEditor::on_tabWidget_Region_Map_currentChanged(int index) {
     }
 }
 
-void RegionMapEditor::on_comboBox_RM_ConnectedMap_activated(const QString &mapsec) {
-    this->ui->lineEdit_RM_MapName->setText(this->project->mapSecToMapHoverName.value(mapsec));
+void RegionMapEditor::on_comboBox_RM_ConnectedMap_textActivated(const QString &mapsec) {
+    this->ui->lineEdit_RM_MapName->setText(this->project->mapSecToMapHoverName->value(mapsec));
     onRegionMapLayoutSelectedTileChanged(this->currIndex);// re-draw layout image
     this->hasUnsavedChanges = true;// sometimes this is called for unknown reasons
 }
 
-void RegionMapEditor::on_comboBox_RM_Entry_MapSection_activated(const QString &text) {
+void RegionMapEditor::on_comboBox_RM_Entry_MapSection_textActivated(const QString &text) {
     this->activeEntry = text;
     this->region_map_entries_item->currentSection = activeEntry;
     updateRegionMapEntryOptions(activeEntry);
diff --git a/src/ui/tileseteditor.cpp b/src/ui/tileseteditor.cpp
index 58f41b24..1054feab 100644
--- a/src/ui/tileseteditor.cpp
+++ b/src/ui/tileseteditor.cpp
@@ -149,8 +149,8 @@ void TilesetEditor::setVersionSpecificUi() {
 
 void TilesetEditor::setMetatileLabelValidator() {
     //only allow characters valid for a symbol
-    QRegExp expression("[_A-Za-z0-9]*$");
-    QRegExpValidator *validator = new QRegExpValidator(expression);
+    QRegularExpression expression("[_A-Za-z0-9]*$");
+    QRegularExpressionValidator *validator = new QRegularExpressionValidator(expression);
     this->ui->lineEdit_metatileLabel->setValidator(validator);
 }
 
@@ -463,7 +463,7 @@ void TilesetEditor::on_checkBox_yFlip_stateChanged(int checked)
     this->metatileLayersItem->clearLastModifiedCoords();
 }
 
-void TilesetEditor::on_comboBox_metatileBehaviors_activated(const QString &metatileBehavior)
+void TilesetEditor::on_comboBox_metatileBehaviors_textActivated(const QString &metatileBehavior)
 {
     if (this->metatile) {
         Metatile *prevMetatile = new Metatile(*this->metatile);