Site Master Pages are only used on publishing pages. This excludes e.g. the views of lists (NewForm.aspx, AllItems.aspx, etc.).
Also while viewing a topic the page is based on a web part Site Page, i.e. not a publishing page.
If you'd like to have custom master pages used on these non publishing pages, you could edit the .aspx -file of the selected pages to use your master page. Briefly put the instructions would be:
- Open your community site on SharePoint Designer
- Open
Site Pages
-> Topic.aspx
-> Edit file
- From the ribbon row select Advanced Mode
- Most likely from row no. 2 you'll find
MasterPageFile="~masterurl/default.master"
. Edit this to refer to your custom master page file (e.g. "~sitecollection/_catalogs/masterpage/CustomMasterPage.master"
)
- Save the changes
- Repeat steps 2-5 on
DispForm.aspx
(etc.) found on Lists and Libraries
-> Discussions List
and on whichever .aspx files you find necessary
Notes:
- I have not tested this solution in this scenario.
- Sometimes when you edit a page in Advanced Mode an informative text
The current page has been customized from its template. Revert to template.
shows up on the page. One way to get rid of the message is explained on entrance's blog.