diff --git a/artiq/gui/explorer.py b/artiq/gui/explorer.py
index 3d7ba9db9..123ad9dca 100644
--- a/artiq/gui/explorer.py
+++ b/artiq/gui/explorer.py
@@ -251,6 +251,7 @@ class ExplorerDock(dockarea.Dock):
         grid.addWidget(self.pipeline, 2, 1)
 
         self.flush = QtGui.QCheckBox("Flush")
+        self.flush.setToolTip("Flush the pipeline before starting the experiment")
         grid.addWidget(self.flush, 2, 2, colspan=2)
 
         submit = QtGui.QPushButton("Submit")
diff --git a/artiq/gui/log.py b/artiq/gui/log.py
index b9c75df05..3c4b1bd99 100644
--- a/artiq/gui/log.py
+++ b/artiq/gui/log.py
@@ -102,6 +102,7 @@ class LogDock(dockarea.Dock):
         self.filterbox = QtGui.QComboBox()
         for item in "DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL":
             self.filterbox.addItem(item)
+        self.filterbox.setToolTip("Display entries at or above this level")
         grid.addWidget(self.filterbox, 0, 1)
         self.filterbox.currentIndexChanged.connect(self.filter_changed)