@EgorUk Documentation for TT2 can be found here.

@EgorUk Opera recognizes that the extension did not come from its "app store" so it generates a random version number (and sometimes a random author name). One way to recognize that you're using a newer version is to click on the Options button, and look at the bottom of the page. If you see 3 checkboxes for various Debug levels, then you have my newest version. Another ToDo item of mine is to add the version number to the top of that Options page.

@EgorUk Sorry about the confusion. One of my ToDo items is to add documentation to my blog. To install the file, open the Extensions page in Opera, then drag&drop the .crx file onto that page. The extension will then appear in the top of the list with an Install button.

@EgorUk Sorry about that. Please try again.

No, it doesn't save Opera Workspaces. You can get similar functionality by using groups and folders in TT2. When you select a group in TT2, you only see the tabs in that group, just like in Workspaces. You can even hide a group in TT2 by right-clicking on it and selecting Hibernate. To bring it back, right-click on any remaining group, select Manager, then click the Load icon next to the group name.

@EgorUk, please see the latest version on my blog, which I just released a few minutes ago.

I took over the development of TreeTabs because it has been abandoned by the original author. I have been struggling for a month or two to learn the code (and refresh my JavaScript knowledge) well enough to support it. I will be submitting TreeTabs2 to the Opera extension store soon.

During my testing, version 2.1.0 reliably saved and restored tabs within groups and folders. By “restore” I mean after a normal browser restart AND using the Import Session tool.

I even tested it using a session that I had saved months ago, and that was also restored correctly.

My original question has been answered, so I will close this issue and open a new one for my crash problem.

Thanks. Although that didn't get rid of the PaintController errors, it stopped the looping, which made the log manageable.

The log is quite cryptic, but it looks like the crash happens here:

[29112:29168:0317/003725.993994:VERBOSE1:url_filter.cc(359)] Invalid rule: /www\.tichyseinblick\.de\/.+\w+\/\w+\.(gif|jpg|png)/
[29112:29168:0317/003725.994028:VERBOSE1:url_filter.cc(359)] Invalid rule: /www\.nw\.de\/.+\w+\/\w+\.(gif|jpg|png)/
[29112:29168:0317/003725.994088:VERBOSE1:url_filter.cc(359)] Invalid rule: /www\.fanfiktion\.de\/.+\w+\/\w+\.(gif|jpg|png)/
[29112:29168:0317/003725.994128:VERBOSE1:url_filter.cc(359)] Invalid rule: /www\.frag-mutti\.de\/.+\w+\/\w+\.(gif|jpg|png)/
[29112:29168:0317/003725.994154:VERBOSE1:url_filter.cc(359)] Invalid rule: /www\.weser-kurier\.de\/.+\w+\/\w+\.(gif|jpg|png)/
[29112:29168:0317/003725.994185:VERBOSE1:url_filter.cc(359)] Invalid rule: /www\.donnerwetter\.de\/.+\w+\/\w+\.(gif|jpg|png)/
[29112:29130:0317/003726.037608:VERBOSE1:content_verifier.cc(595)] OnFetchComplete hhhfihlmbcifeafjbbjfkclpofddkalf success:1
[29112:29130:0317/003726.039130:VERBOSE1:content_verifier.cc(595)] OnFetchComplete kgogikjfdpdkoedplfagjjcfodbokblg success:1
[29112:29130:0317/003726.043473:VERBOSE1:content_verifier.cc(595)] OnFetchComplete kipjbhgniklcnglfaldilecjomjaddfi success:1
[29112:29130:0317/003726.060958:VERBOSE1:content_verifier.cc(595)] OnFetchComplete mjfdcfnlgkhmadiafkpopgifghhgoaif success:1
[29112:29130:0317/003726.072405:VERBOSE1:content_verifier.cc(595)] OnFetchComplete mmmbddcnnndpbdflpccgcknaaabgldak success:1
[29112:29112:0317/003726.128330:VERBOSE1:top_active_pages.cc(50)] Received history query results.
[29112:29112:0317/003726.128412:VERBOSE1:partner_offer_history_fetcher_composite.cc(55)] Fetched transaction 0, remaining tasks: 1
[29329:1:0317/003726.186601:ERROR:child_thread_impl.cc(858)] Receiver for unknown Channel-associated interface: chrome.mojom.SearchBouncer
[29335:1:0317/003726.208600:ERROR:child_thread_impl.cc(858)] Receiver for unknown Channel-associated interface: chrome.mojom.SearchBouncer
[29112:29112:0317/003726.218161:WARNING:x11_util.cc(1415)] X error received: serial 686, error_code 10 (BadAccess (attempt to access private resource 
denied)), request_code 33, minor_code 0 (X_GrabKey)
[29112:29112:0317/003726.218752:WARNING:x11_util.cc(1415)] X error received: serial 687, error_code 10 (BadAccess (attempt to access private resource 
denied)), request_code 33, minor_code 0 (X_GrabKey)
[29112:29112:0317/003726.218978:WARNING:x11_util.cc(1415)] X error received: serial 688, error_code 10 (BadAccess (attempt to access private resource 
denied)), request_code 33, minor_code 0 (X_GrabKey)
[29112:29112:0317/003726.219024:WARNING:x11_util.cc(1415)] X error received: serial 690, error_code 10 (BadAccess (attempt to access private resource 
denied)), request_code 33, minor_code 0 (X_GrabKey)
[29368:1:0317/003726.232408:ERROR:child_thread_impl.cc(858)] Receiver for unknown Channel-associated interface: chrome.mojom.SearchBouncer
[29372:1:0317/003726.307223:ERROR:child_thread_impl.cc(858)] Receiver for unknown Channel-associated interface: chrome.mojom.SearchBouncer
[29377:1:0317/003726.336040:ERROR:child_thread_impl.cc(858)] Receiver for unknown Channel-associated interface: chrome.mojom.SearchBouncer
[29112:29112:0317/003726.341142:VERBOSE1:session_recorder_impl.cc(518)] [initial_context] 861b
[29399:1:0317/003726.357376:ERROR:child_thread_impl.cc(858)] Receiver for unknown Channel-associated interface: chrome.mojom.SearchBouncer
[29755:1:0317/003726.364178:VERBOSE1:sandbox_linux.cc(69)] Activated seccomp-bpf sandbox for process type: renderer.
[29112:29112:0317/003726.394620:VERBOSE1:top_active_pages.cc(50)] Received history query results.
[29149:29156:0317/003726.396094:VERBOSE1:network_delegate.cc(32)] NetworkDelegate::NotifyBeforeURLRequest: https://duckduckgo.com/?q=firefox+%22browse
r.tabs.get%22&t=opera&ia=web
[29456:1:0317/003726.418500:ERROR:child_thread_impl.cc(858)] Receiver for unknown Channel-associated interface: chrome.mojom.SearchBouncer
[29763:1:0317/003726.453416:VERBOSE1:sandbox_linux.cc(69)] Activated seccomp-bpf sandbox for process type: renderer.
[29399:1:0317/003726.463551:ERROR:paint_controller.cc(548)] PaintController::FinishCycle() completed
[29458:1:0317/003726.465874:ERROR:child_thread_impl.cc(858)] Receiver for unknown Channel-associated interface: chrome.mojom.SearchBouncer
[29766:1:0317/003726.470674:VERBOSE1:sandbox_linux.cc(69)] Activated seccomp-bpf sandbox for process type: renderer.
[29329:1:0317/003726.514292:ERROR:paint_controller.cc(548)] PaintController::FinishCycle() completed

I'm trying to debug my extension that crashes Opera during a long-running process. So I start Opera with verbose logging enabled (opera --enable-logging --v=1 &).

The crash doesn't happen because Opera is stuck in an endless loop displaying this "error" hundreds of times per second:

ERROR:paint_controller.cc(548)] PaintController::FinishCycle() completed

I searched in about:flags, but did not find a way to disable the PaintController.

TreeTabs2 is available here.

@oloko: I have tried to contact the author to offer development assistance, but he has not responded. Please see TreeTabs2 for a newer version of this extension.