I had to reinstall my Linux and now the first monitor detected is the left monitor, which fixes my problem.
I've tested now with DC moved on the right monitor

Test case:
1. Open DC, move to right monitor
2. Open viewer, move to right monitor, close viewer
3. Open editor, leave it on the left monitor, close editor.
I've maximized both viewer and editor. The maximize property is persisted correctly.
Here is the settings file:
Code:
[TfrmOptions(1600x900)]
TfrmOptions_Height=616
TfrmOptions_Width=995
TfrmOptions_WindowState=wsNormal
TfrmOptions_Left=1902
TfrmOptions_Top=142
[TfrmEditor(1600x900)]
TfrmEditor_Height=851
TfrmEditor_Width=1600
TfrmEditor_WindowState=wsMaximized
TfrmEditor_Left=0
TfrmEditor_Top=0
[TfrmViewer(1600x900)]
TfrmViewer_Height=851
TfrmViewer_Width=1600
TfrmViewer_Left=1600
TfrmViewer_Top=0
TfrmViewer_WindowState=wsMaximized
[TfrmMain(1600x900)]
nbConsole_Height=54
seLogWindow_Height=51
[TfrmFileAssoc(1600x900)]
TfrmFileAssoc_Height=585
TfrmFileAssoc_Width=568
TfrmFileAssoc_WindowState=wsNormal
TfrmFileAssoc_Left=516
TfrmFileAssoc_Top=157
[TfrmFindDlg(1600x900)]
TfrmFindDlg_Height=427
TfrmFindDlg_Left=466
TfrmFindDlg_Top=236
TfrmFindDlg_Width=667
TfrmFindDlg_WindowState=wsNormal
[TfColumnsSetConf(1600x900)]
TfColumnsSetConf_Height=583
TfColumnsSetConf_Width=900
TfColumnsSetConf_WindowState=wsNormal
TfColumnsSetConf_Left=350
TfColumnsSetConf_Top=158
From the settings file you can see that the viewer is on the right monitor, which means
there is a bug at the restoring part.
Cheers.