Fill with BG Color

`Ctrl` + `.`

All hotkeys for GIMP

Help Help	`F1`
Help Context Help	`↑ Shift` + `F1`
Toolbox Rect Select	`R`
Toolbox Ellipse Select	`E`
Toolbox Free Select	`F`
Toolbox Fuzzy Select	`U`
Toolbox Select By Color	`↑ Shift` + `O`
Toolbox Scissors	`I`
Toolbox Paths	`B`
Toolbox Color Picker	`O`
Toolbox Move	`M`
Toolbox Crop and Resize	`↑ Shift` + `C`
Toolbox Rotate	`↑ Shift` + `R`
Toolbox Scale	`↑ Shift` + `T`
Toolbox Shear	`↑ Shift` + `S`
Toolbox Perspective	`↑ Shift` + `P`
Toolbox Flip	`↑ Shift` + `F`
Toolbox Text	`T`
Toolbox Bucket Fill	`↑ Shift` + `B`
Toolbox Blend	`L`
Toolbox Pencil	`N`
Toolbox Paintbrush	`P`
Toolbox Eraser	`↑ Shift` + `E`
Toolbox Airbrush	`A`
Toolbox Ink	`K`
Toolbox Clone	`C`
Toolbox Convolve	`V`
Toolbox Smudge	`S`
Toolbox Dodge/Burn	`↑ Shift` + `D`
Toolbox Swap Colors	`X`
Toolbox Default Colors	`D`
File New image	`Ctrl` + `N`
File Open image	`Ctrl` + `O`
File Open image as new layer	`Ctrl` + `Alt` + `O`
File Duplicate image	`Ctrl` + `D`
File Open recent image 01	`Ctrl` + `1`
File Open recent image 02	`Ctrl` + `2`
File Open recent image 03	`Ctrl` + `3`
File Open recent image 04	`Ctrl` + `4`
File Open recent image 05	`Ctrl` + `5`
File Open recent image 06	`Ctrl` + `6`
File Open recent image 07	`Ctrl` + `7`
File Open recent image 08	`Ctrl` + `8`
File Open recent image 09	`Ctrl` + `9`
File Open recent image 10	`Ctrl` + `0`
File Save image	`Ctrl` + `S`
File Save under a new name	`↑ Shift` + `Ctrl` + `S`
File Quit	`Ctrl` + `Q`
Dialogs Layers	`Ctrl` + `L`
Dialogs Brushes	`↑ Shift` + `Ctrl` + `B`
Dialogs Patterns	`↑ Shift` + `Ctrl` + `P`
Dialogs Gradients	`Ctrl` + `G`
View Toggle guides	`↑ Shift` + `Ctrl` + `T`
Dialogs Palettes	`Ctrl` + `P`
Dialogs Info window	`↑ Shift` + `Ctrl` + `I`
Dialogs Navigation window	`↑ Shift` + `Ctrl` + `N`
Dialogs Close the window	`Alt` + `F4`
Dialogs Jump to next widget	`⭾ Tab`
Dialogs Jump to previous widget	`↑ Shift` + `⭾ Tab`
Dialogs Set the new value	`⤶ Enter`
Dialogs Activate current button or list	`Space`
Dialogs In a multi-tab dialog, switch tabs	`Ctrl` + `Alt` + `Page Up`
Dialogs Open Location	`↑ Shift` + `L`
Dialogs Up-Folder	`Alt` + `↑`
Dialogs Down-Folder	`Alt` + `↓`
Dialogs Home-Folder	`Alt` + `Home`
Dialogs Close Dialog	`Esc`
View Main Menu	`F10`
View Drop-down Menu	`↑ Shift` + `F10`
View Toggle fullscreen	`F11`
View Toggle quickmask	`↑ Shift` + `Q`
View Close document window	`Ctrl` + `W`
View Zoom out	+ `or Ctrl` + `Mouse wheel up and down`
View Zoom 1:1	`1`
View Shrink wrap	`Ctrl` + `E`
View Fit image in window	`↑ Shift` + `Ctrl` + `E`
View Toggle rulers	`↑ Shift` + `Ctrl` + `R`
View Undo	`Ctrl` + `Z`
View Redo	`Ctrl` + `Y`
View Copy selection	`Ctrl` + `C`
View Cut selection	`Ctrl` + `X`
View Copy visible	`Ctrl` + `↑ Shift` + `C`
View Paste as new image	`Ctrl` + `↑ Shift` + `V`
View Paste clipboard	`Ctrl` + `V`
View Clears selection	`Ctrl` + `K`
View Named copy selection	`↑ Shift` + `Ctrl` + `C`
View Named cut selection	`↑ Shift` + `Ctrl` + `X`
View Named paste clipboard	`↑ Shift` + `Ctrl` + `V`
View Fill with FG Color	`Ctrl` + `,`
View Fill with BG Color	`Ctrl` + `.`
View Fill with Pattern	`Ctrl` + `:`
Layers Select the layer above	`Page Up`
Layers Select the layer below	`Page Down`
Layers Select the first layer	`Home`
Layers Select the last layer	`End`
Layers Merge visible layers	`Ctrl` + `M`
Layers Anchor layer	`Ctrl` + `H`
Selections Toggle selections	`Ctrl` + `T`
Selections Select all	`Ctrl` + `A`
Selections Select none	`↑ Shift` + `Ctrl` + `A`
Selections Invert selection	`Ctrl` + `I`
Selections Float selection	`↑ Shift` + `Ctrl` + `L`
Selections Path to selection	`↑ Shift` + `V`
Plugins Repeat last plug-in	`Ctrl` + `F`
Plugins Reshow last plug-in	`↑ Shift` + `Ctrl` + `F`