diff --git a/artiq/frontend/artiq_gui.py b/artiq/frontend/artiq_gui.py
index 2db26042b..645643fb5 100755
--- a/artiq/frontend/artiq_gui.py
+++ b/artiq/frontend/artiq_gui.py
@@ -66,7 +66,7 @@ def main():
     win.resize(1400, 800)
     win.setWindowTitle("ARTIQ")
 
-    d_explorer = ExplorerDock(status_bar, schedule_ctl)
+    d_explorer = ExplorerDock(win, status_bar, schedule_ctl)
     loop.run_until_complete(d_explorer.sub_connect(
         args.server, args.port_notify))
     atexit.register(lambda: loop.run_until_complete(d_explorer.sub_close()))
diff --git a/artiq/gui/explorer.py b/artiq/gui/explorer.py
index 4b4529cfd..e4d594969 100644
--- a/artiq/gui/explorer.py
+++ b/artiq/gui/explorer.py
@@ -1,10 +1,12 @@
 import asyncio
+import traceback
 
 from quamash import QtGui, QtCore
 from pyqtgraph import dockarea
 from pyqtgraph import LayoutWidget
 
 from artiq.protocols.sync_struct import Subscriber
+from artiq.protocols import pyon
 from artiq.gui.tools import DictSyncModel
 
 
@@ -21,20 +23,68 @@ class _ExplistModel(DictSyncModel):
         return k
 
 
+class _FreeValueEntry(QtGui.QLineEdit):
+    def __init__(self, procdesc):
+        QtGui.QLineEdit.__init__(self)
+        if "default" in procdesc:
+            self.insert(pyon.encode(procdesc["default"]))
+
+    def get_argument_value(self):
+        return pyon.decode(self.text())
+
+
+_procty_to_entry = {
+    "FreeValue": _FreeValueEntry
+}
+
+
+class _ArgumentSetter(LayoutWidget):
+    def __init__(self, dialog_parent, arguments):
+        LayoutWidget.__init__(self)
+        self.dialog_parent = dialog_parent
+
+        if not arguments:
+            self.addWidget(QtGui.QLabel("No arguments"), 0, 0)
+
+        self._args_to_entries = dict()
+        for n, (name, procdesc) in enumerate(arguments):
+            self.addWidget(QtGui.QLabel(name), n, 0)
+            entry = _procty_to_entry[procdesc["ty"]](procdesc)
+            self.addWidget(entry, n, 1)
+            self._args_to_entries[name] = entry
+
+    def get_argument_values(self):
+        r = dict()
+        for arg, entry in self._args_to_entries.items():
+            try:
+                r[arg] = entry.get_argument_value()
+            except:
+                msgbox = QtGui.QMessageBox(self.dialog_parent)
+                msgbox.setWindowTitle("Error")
+                msgbox.setText("Failed to obtain value for argument '{}'.\n{}"
+                               .format(arg, traceback.format_exc()))
+                msgbox.setStandardButtons(QtGui.QMessageBox.Ok)
+                msgbox.show()
+                return None
+        return r
+
+
 class ExplorerDock(dockarea.Dock):
-    def __init__(self, status_bar, schedule_ctl):
+    def __init__(self, dialog_parent, status_bar, schedule_ctl):
         dockarea.Dock.__init__(self, "Explorer", size=(1500, 500))
 
+        self.dialog_parent = dialog_parent
         self.status_bar = status_bar
         self.schedule_ctl = schedule_ctl
 
-        splitter = QtGui.QSplitter(QtCore.Qt.Horizontal)
-        self.addWidget(splitter)
+        self.splitter = QtGui.QSplitter(QtCore.Qt.Horizontal)
+        self.addWidget(self.splitter)
 
         grid = LayoutWidget()
-        splitter.addWidget(grid)
+        self.splitter.addWidget(grid)
 
         self.el = QtGui.QListView()
+        self.el.selectionChanged = self.update_argsetter
         grid.addWidget(self.el, 0, 0, colspan=4)
 
         self.datetime = QtGui.QDateTimeEdit()
@@ -63,8 +113,22 @@ class ExplorerDock(dockarea.Dock):
         grid.addWidget(submit, 3, 0, colspan=4)
         submit.clicked.connect(self.submit_clicked)
 
-        placeholder = QtGui.QWidget()
-        splitter.addWidget(placeholder)
+        self.argsetter = _ArgumentSetter(self.dialog_parent, [])
+        self.splitter.addWidget(self.argsetter)
+        self.splitter.setSizes([grid.minimumSizeHint().width(), 1000])
+
+    def update_argsetter(self, selected, deselected):
+        selected = selected.indexes()
+        if selected:
+            row = selected[0].row()
+            key = self.explist_model.row_to_key[row]
+            expinfo = self.explist_model.backing_store[key]
+            arguments = expinfo["arguments"]
+            sizes = self.splitter.sizes()
+            self.argsetter.deleteLater()
+            self.argsetter = _ArgumentSetter(self.dialog_parent, arguments)
+            self.splitter.insertWidget(1, self.argsetter)
+            self.splitter.setSizes(sizes)
 
     def enable_duedate(self):
         self.datetime_en.setChecked(True)
@@ -106,7 +170,10 @@ class ExplorerDock(dockarea.Dock):
                 due_date = self.datetime.dateTime().toMSecsSinceEpoch()/1000
             else:
                 due_date = None
+            arguments = self.argsetter.get_argument_values()
+            if arguments is None:
+                return
             asyncio.async(self.submit(self.pipeline.text(),
                                       expinfo["file"], expinfo["class_name"],
-                                      dict(), self.priority.value(), due_date,
-                                      self.flush.isChecked()))
+                                      arguments, self.priority.value(),
+                                      due_date, self.flush.isChecked()))