This must be new. I have 16.04, and there is no <application class> entry.
OP wrote:
It worked in past versions of Lubuntu, but in 16.10 it was having no effectSo it seems to have started in 16.10.
I never really looked at this in 16.04 or 14.04 because I don't mind the new application gaining focus.
Re. there is no <application class> entry, the last section of lubuntu-rc.xml in Lubuntu 16.04 has this
<applications>
<!--
# this is an example with comments through out. use these to make your
# own rules, but without the comments of course.
# you may use one or more of the name/class/role/title/type rules to specify
# windows to match
<application name="the window's _OB_APP_NAME property (see obxprop)"
class="the window's _OB_APP_CLASS property (see obxprop)"
role="the window's _OB_APP_ROLE property (see obxprop)"
title="the window's _OB_APP_TITLE property (see obxprop)"
type="the window's _OB_APP_TYPE property (see obxprop)..
(if unspecified, then it is 'dialog' for child windows)">
# you may set only one of name/class/role/title/type, or you may use more
# than one together to restrict your matches.
# the name, class, role, and title use simple wildcard matching such as those
# used by a shell. you can use * to match any characters and ? to match
# any single character.
# the type is one of: normal, dialog, splash, utility, menu, toolbar, dock,
# or desktop
# when multiple rules match a window, they will all be applied, in the
# order that they appear in this list
# each rule element can be left out or set to 'default' to specify to not
# change that attribute of the window
<decor>yes</decor>
# enable or disable window decorations
<shade>no</shade>
# make the window shaded when it appears, or not
<position force="no">
# the position is only used if both an x and y coordinate are provided
# (and not set to 'default')
# when force is "yes", then the window will be placed here even if it
# says you want it placed elsewhere. this is to override buggy
# applications who refuse to behave
<x>center</x>
# a number like 50, or 'center' to center on screen. use a negative number
# to start from the right (or bottom for <y>), ie -50 is 50 pixels from the
# right edge (or bottom).
<y>200</y>
<monitor>1</monitor>
# specifies the monitor in a xinerama setup.
# 1 is the first head, or 'mouse' for wherever the mouse is
</position>
<focus>yes</focus>
# if the window should try be given focus when it appears. if this is set
# to yes it doesn't guarantee the window will be given focus. some
# restrictions may apply, but Openbox will try to
<desktop>1</desktop>
# 1 is the first desktop, 'all' for all desktops
<layer>normal</layer>
# 'above', 'normal', or 'below'
<iconic>no</iconic>
# make the window iconified when it appears, or not
<skip_pager>no</skip_pager>
# asks to not be shown in pagers
<skip_taskbar>no</skip_taskbar>
# asks to not be shown in taskbars. window cycling actions will also
# skip past such windows
<fullscreen>yes</fullscreen>
# make the window in fullscreen mode when it appears
<maximized>true</maximized>
# 'Horizontal', 'Vertical' or boolean (yes/no)
</application>
# end of the example
-->
<!-- Option to maximize all normal window when launched-->
<!--
<application type="normal">
<maximized>true</maximized>
</application>
-->
</applications>So it's basically all commented out and then it's for the user to add stuff. For example, I have
<application class="Lxterminal" name="lxterminal">
<position force="yes">
<x>-0</x>
<y>0</y>
</position>
<decor>no</decor>
</application>
and
<application class="Galculator">
<position force="yes">
<x>500</x>
<y>300</y>
</position>
</application>