My feedback

[maXmo]

In list mode look and feel should better match that of explorer:
1. columns make little sense, should be ability to remove them, common sorting options should be accessible from menu instead
2. file name should fit window, not constrained by name column
3. when cursor is in a list column, which is partially visible in panel, the panel should be scrolled to display the column
4. pressing right at the last file does strange thing: shows the beginning of the list without moving cursor

Accessibility:
1. dialogs in panel tabs should use dialog font instead of file list font - they serve different purposes (I prefer file list font Verdana 12pt, yet it's not good for dialogs)
2. dialogs in panel tabs are a little contradictory: dialog controls should be navigable with `tab` key, but it's already reserved for panel switching; they should be probably done as normal dialogs (modeless if desired); also "Save" and "Apply" buttons look a little non-traditional, usually it's "Apply" to apply without closing and "OK" to apply with closing
3. "Column settings" dialog doesn't fit in my display (1366*768, 125% DPI) and I couldn't find buttons with keyboard - probably messed tabstops (tried to remove columns)

Settings:
1. FocusRect color... is it inverted??? Any way to make it solid and add background?

[Mathias (Author)]

In list mode look and feel should better match that of explorer:
1. columns make little sense, should be ability to remove them, common sorting options should be accessible from menu instead
2. file name should fit window, not constrained by name column
3. when cursor is in a list column, which is partially visible in panel, the panel should be scrolled to display the column
4. pressing right at the last file does strange thing: shows the beginning of the list without moving cursor

1. No they do make sense. Columns are needed for sorting. and for sizing the width the list columns.
2. No. if you have 1 file with very long file name and the rest short then everything would be very wide for nothing.
 and if you have very long file name you might want to show the view with cut files names "filena...txt" so that you can view many files in the list
even if the filenames are long
3. It is.. most of the time. It depends on how much of a partial columns is shown
4. I noticed. That is something new, It was not like that before. Add the vertical scrolling support must have broken something. ( As I said it would )

Accessibility:
1. dialogs in panel tabs should use dialog font instead of file list font - they serve different purposes (I prefer file list font Verdana 12pt, yet it's not good for dialogs)
2. dialogs in panel tabs are a little contradictory: dialog controls should be navigable with `tab` key, but it's already reserved for panel switching; they should be probably done as normal dialogs (modeless if desired); also "Save" and "Apply" buttons look a little non-traditional, usually it's "Apply" to apply without closing and "OK" to apply with closing
3. "Column settings" dialog doesn't fit in my display (1366*768, 125% DPI) and I couldn't find buttons with keyboard - probably messed tabstops (tried to remove columns)

1. Dialogs in panel ??
2. All dialogs are navigatable by tab key
3. Set DPI to 100% and it will fit , Sorry , I know that dialog is big. Not sure I will redesign it. Might be possible to tighten it up a litten.
But not sure that will help

Settings:
1. FocusRect color... is it inverted??? Any way to make it solid and add background?

1. I know. And I blame Windows. The API functions to draw the focus rectangle is drawing using by XOR against the background with the set color.
   And by doing so the result of the color does not match.
   I'm planing on adding own code for it. But other things have been more important to add.

   The background can be configured. Just make sure the "Use File/folder specified background colors" is enabled. else the
   default background colors is used for all items.

[maXmo]

1. Dialogs in panel ??
2. I know. And I blame Windows. The API functions to draw the focus rectangle is drawing using by XOR against the background with the set color.
   And by doing so the result of the color does not match.
3. The background can be configured. Just make sure the "Use File/folder specified background colors" is enabled. else the
   default background colors is used for all items.

1. Yeah, the major ones: "Core settings" and "Explorer panel settings". Looks like they're not navigable with tab key.
2. Maybe, given a desired color, there's an easy trick to figure out, what color to use in drawing, so that xoring will give the desired color?
3. Background to the FocusRect, not to all files.

[maXmo]

Looks like if you specify color (r,g,b), it draws with color (255-r,255-g,255-b). So if you draw with color (255-r,255-g,255-b), the result will be (r,g,b) - as specified by user.

Edit: or maybe I just have white background?

[Mathias (Author)]

1. Dialogs in panel ??
2. I know. And I blame Windows. The API functions to draw the focus rectangle is drawing using by XOR against the background with the set color.
   And by doing so the result of the color does not match.
3. The background can be configured. Just make sure the "Use File/folder specified background colors" is enabled. else the
   default background colors is used for all items.

1. Yeah, the major ones: "Core settings" and "Explorer panel settings". Looks like they're not navigable with tab key.
2. Maybe, given a desired color, there's an easy trick to figure out, what color to use in drawing, so that xoring will give the desired color?
3. Background to the FocusRect, not to all files.

1. Ahh the Settings panel. well it is not a "dialog" so I can not be navigated by tab.
2. No it is not easy. It depends on what color happens to be there and what color that is depend on settings and yo can have different color for different state like selected / focused and so on.
3. No the focus ndicator is just line around the area. It has no background..  If you want to have a different background on item in focus then it is the "Focus" and "Selected and in Focus" color item you need to change.