1: https://en.wikipedia.org/wiki/File_manager#Orthodox_file_man...
If you sell your own brand of cornflakes, with a distinct box, even if you contract the exact same third party cornflake producing plant (i.e. exactly what happens in the laundry detergent industry), that's competition. If you make your cornflakes available for free, and you use basically the same packaging as Kellogg's to the point where if you showed both to someone unfamiliar with the exact styling queues they'd go "... aren't these the same?" that's laws being broken.
And from the screenshots, this sure does look identical to Total Commander. So again: is this actually legal? (it might be, I don't know, which is why I asked)
But the two-panel file management paradigm predates Total Commander by many years - TC itself copied NC - so I doubt they would be able to patent anything worthwhile even if they tried.
1. A substantially similar product
I think we both agree this is legal (given your laundry detergent example)
2. Confusion for the original product in marketing materials (including packaging)
- This relates primarily to trademarks law; I partially addressed this in my original comment pointing out that simply the name being of the form "X Commander" isn't likely an enforceable trademark.
- The DC homepage has a screenshot, then some text, which includes the text "it is inspired by Total Commander." This seems analogous to a picture of cornflakes followed by "compare to Kellogg's Cornflakes"
3. The UI looking an awful lot like TC
If the icons TC used were copyrighted, and DC used them, that's clear copyright infringement, but I don't think this is being alleged here.
This gets complicated quickly; the general layout (status bar at top, clickable reminders of keyboard shortcuts at bottom, two side-by-side panes, &c) did not originate with TC, so if DC is in trouble for this, it's not with TC
The great similarity in the general look is at least partly to them both using Lazarus, and partly intentional to make it easier to use by existing TC users.
The similarities just from using the same toolkit are generally fine. I think the point you are raising that when combined with the intentional layout similarities this could rise to the level of product confusion; if the buttons all looked very different, but were in the same screen positions and did the exact same things, then DC would look very different from TC.
As far as copying the "look and feel" Lotus v. Borland strongly suggests that the interface of an application is not subject to copyright. If TC had a design patent or trademark on the menu or toolbar look, then they could almost certainly enforce this, but it would have had to have been registered in advance.
Christian Ghisler has been developing Total Commander for 27 years, since 1995. While he didn't invent the idea of two-pane file manager and more or less reimplemented Norton Commander in proper graphics-mode GUI, he added so much more to it over those three decades that it wouldn't be right to call it a copy of NC; moreover, he didn't ship it for free, he priced it at the same $49.
What the author of Copy, sorry, Double Commander does is pure and simple dumping. It's like standing next to a bakery and giving away same cakes for free. Does that feel right?
I wonder how the development of Double Commander is backed financially.
>Double Commander is absolutely free <,comma> open source software.
Implies free as in beer as well, unless someone rubs my nose into the price stated somewhere on the website.