Using two splitters instead of one to make positioning easier.

tests/reference/novelwriter.conf

@@ -4,7 +4,8 @@ timestamp = 2019-05-18 15:06:44
 [Sizes]
 geometry = 1100, 650
 treecols = 120, 30, 50
-mainpane = 300, 400, 400
+mainpane = 300, 800
+docpane = 400, 400
 
 [Project]
 autosaveproject = 60

tests/test_config.py

@@ -70,7 +70,8 @@ def testConfigSetMainPanePos(nwTemp,nwRef):
     refConf = path.join(nwRef, "novelwriter.conf")
     assert theConf.setMainPanePos([0, 0])
     assert theConf.confChanged
-    assert theConf.setMainPanePos([300, 400, 400])
+    assert theConf.setMainPanePos([300, 800])
+    assert theConf.setDocPanePos([400, 400])
     assert theConf.saveConfig()
     assert cmpFiles(tmpConf, refConf, [2])
     assert not theConf.confChanged