I tested with Version 7.0.3.1123.
PSD seems to use system proxy settings (the one set eg. from Control Panel or Internet Explorer). But it fails to use authentication: it closes the connection when gets HTTP 407 from our proxy server.
I check with another proxy. Now, PSD gets the below answer, but it fails to use it (displayed version is still 9.0.6.1665):
date=05042013
[plsqldev.exe]
Version=10.0.2.1697
WhatsNew=http://www.allroundautomations.com/registered/pls1002.txt
Download=http://download.allroundautomations.com/plsqldev1002.exe
Update=http://download.allroundautomations.com/plsqldev1002.upd
[plsqldoc.dll]
Version=1.2.2.0
ReleaseDate=
WhatsNew=Fixed "List index out of bounds" error during document generation
Download=
http://www.allroundautomations.com/download/plsqldoc122.zip
[vcs.dll]
Version=1.2.4.0
ReleaseDate=
WhatsNew=Upgraded to work with PL/SQL Developer 9.0
Download=http://www.allroundautomations.com/download/vcs124.zip
[redgate.dll]
Version=1.1.1.134
ReleaseDate=
WhatsNew=Improved download and Installation of Red Gate products from within Plug-In
Download=http://www.allroundautomations.com/download/RedGate111.zip
[ftp.dll]
Version=2.1.0.0
ReleaseDate=
WhatsNew=New version with Timezone correction and some bugfixes.
Download=http://www.allroundautomations.com/download/ftp2.zip
[textexport.dll]
Version=1.1.0.0
ReleaseDate=
WhatsNew=New: allow columns to be included/excluded from export, allow first column (Line No) always include/exclude from export
Download=http://www.allroundautomations.com/download/textexport.zip
[activequerybuilder.dll]
Version=1.1.0.0
ReleaseDate=
WhatsNew=New: Updated for PL/SQL Developer 7.1
Download=http://www.allroundautomations.com/download/ActiveQueryBuilder.zip
[plotwindow.dll]
Version=1.1.0.0
WhatsNew=http://www.browserextender.com/forum/viewtopic.php?p=24#24
Download=http://www.browserextender.com/downloads.php?language=english#PlotWindow
[OB5.dll]
Version=
ReleaseDate=02022006
WhatsNew=http://www.orindasoft.com/public/Pages.php4?location=plsqlfeatures
Download=http://www.orindasoft.com/public/V4%20Patchestwo.php4
[QuickER.dll]
Version=2.6.0.54
WhatsNew=http://www.gotterup.net/release_notes.txt
Download=http://www.gotterup.net/quicker.exe
[QuickERPlugIn.dll]
Version=2.6.0.54
WhatsNew=http://www.gotterup.net/release_notes.txt
Download=http://www.gotterup.net/quicker.exe